WASHINGTON (CNN) -- These days, Marchelle Roberts is a confident 22-year-old who smiles easily and talks excitedly about her plans for the future.
But the rising senior at Philadelphia's Temple University had to travel a long and difficult road to get to where she is today.
Roberts was taken away from her parents when she was 7 years old. She still remembers vividly the day that long journey began, when a woman she had never seen before and hasn't seen since came in a car to get her and her brother Shawn, who was 3 or 4 years old.
"It was pretty scary for me," Roberts said. "My brother and I were in the back with a bag full of both of our belongings. My biological mother got out of the car and the lady kept driving, and she drove to someone else's house and she told us we'd be staying there, and she left. And so nobody really explained to me what foster care was, or what being taken away from your parents meant, or how long it would be for or why it happened."
Roberts spent five years in foster care in Camden, New Jersey, shuttling from one family to the next. During that time, Roberts said, she suffered sexual abuse and her brother suffered emotional abuse.
"If it wasn't me being abused then it was me seeing my brother being abused, which was more difficult for me," she said. "I felt strong enough to endure the abuse as long as my brother didn't have to go through it, and so I would always try to be there, like after school. I would try to make sure I got home and was just there with my brother to make sure he was OK."
She was eventually removed from that situation and ended up with Lisa Roberts, who later adopted her, adding to a growing family of adopted children. But during the process she and her brother were separated. Marchelle hasn't seen Shawn in 12 years.
Now she is one of 15 former foster children participating in the Foster Youth Internship program run by the Congressional Coalition on Adoption Institute. The program aims to give former foster children an opportunity to help shape public policy on child welfare issues. Interns spend the summer working in the offices of members of Congress from both parties. At the end of the program, they make a presentation to the entire Congress with recommendations on how to improve the foster care system.
The interns live in a college dormitory and have weekly dinners to talk about their experiences on the Hill and growing up in the system. They also get a stipend for a business wardrobe and informal career counseling from the Sara Start Fund for Foster Youth, an organization that works with CCAI to help them get a start on their professional lives.
The program is competitive, about 250 young people apply each year and applicants must have completed at least one semester of college. CCAI Executive Director Kathleen Strottman said the young people who are accepted are the cream of the crop. Former interns have gone on to clerkships and to various positions in state government. Nearly half have entered careers in social service.
"We find that the youth who have survived foster care are, by their nature, more problem solvers," Strottman said. "So what better people to bring to bear on a problem that really needs to be solved?"
Pushing for change
Roberts survived that system and says there's a lot she wants to see changed. She wants to create a one-stop online clearinghouse laying out the resources available to foster youth and former foster youth all across the country, and she wants states to do more to keep siblings together in foster care.
"It's not just keeping them together, but making sure that they're in stable environments," she said. "In the system, youth are taken away from -- most of the times -- their biological parents because they're suffering from some kind abuse or something like that, and so I don't think that being placed into a home where you suffer the same things solves much."
She has been interning in the office of Sen. Mary Landrieu, D-Louisiana, who had her own encounter with an orphan at a young age and has been an advocate for foster children and orphans since she was first elected to office.
"When I was a child, a young teenager, I literally found a little 9-year-old sleeping in a park and it was just horrifying to me that a child would be alone sleeping anywhere, let alone sleeping in a park," Landrieu said during an interview in her Capitol Hill office. "I brought him home and that was my beginning of understanding about a child that was homeless, living with a grandmother incapable of raising him. And then, of course, he went through the foster care system, and that's when I learned how broken it was."
Landrieu, who helped create the internship program 10 years ago, said a tax credit to help families adopt and a program that helps provide education, and training vouchers to foster youth as they transition out of the system, have helped, but more needs to be done to improve the system.
"The foster care interns that come to Washington learn a lot about the system here and how it affects their lives and the lives of children in foster care all over America, which are about 500,000," Landrieu said. "But most importantly, it educates members of Congress and their staffs about what really happens in our foster care system, and we think out of this great changes for the better will occur."
Roberts is still searching for her younger brother, who she believes would be 17 or 18 years old now.
"I worry constantly," she said. "I was able to be adopted and I had a lovely life and all these siblings that love me, I have a mom who loves me, you know I'm just living a great life right now. And I don't know if his situation was as blessed as mine was.
"And then there's also -- he could have been bouncing around from foster home to foster home and I wasn't. He could have been adopted and it's possible his adoptive family didn't want him to have contact with his biological family, and I think about those things all the time."
When she graduates in the winter, Roberts plans to pursue a career in broadcast journalism -- a field she loves and that she hopes might one day help Shawn find her.
For now, she feels fortunate to have had what she calls a once-in-a-lifetime opportunity to spend a summer in the halls of Congress and to share her story.
"There are so many things I want people to know," she said. "One of the main things that I want people to know is that foster youth count."
CNN's NuNu Japaridze contributed to this story.