How can we get medical papers signs for a person with CP?

Question: So my partner needs a doctors signature to apply for rides to work through the disability services bus, as well as to get a handicap parking permit. We went to the medi-center this morning to have them sign the forms for her, and they said that they could not, it had to be someone who was familiar with Monica and her condition.
The problem is that she hasnt been to a doctor in 6 years. She didnt have a steady pediatrician as a child, and her orthopedic surgeon, the only person she saw regularly, has been retired for 10 years and they do not have records from that long ago. We have none of her medical records, either.
So we are stuck at this point. She needs to get the forms signed ASAP. But they are telling us that no one will be able to sign them if she is a new patient, she has to have history.
SHE IS DISABLED. No, she is not in a wheelchair, she has Spastic CP and just has a slight limp, but she has mobility issues and NEEDS ASSISTANCE. No one is willing to help us out.