How the heck do I manage the next hurtle?

So, here I am asking the world for help. Its been a very long day, in a very long life time. I try to keep a sense of humor about what has been happening but, I am failing. I recently discovered I am going blind, I now need a wheelchair, and have no way to pay for a car. I am sorry to even say it. I am frustrated. My medical file is very thick and is full of the rare diseases used for trick questions on the Medical Boards. I go into the teaching hospital and spend six hours waiting for the medical students to finish asking their questions so I can get medical help. I suffer from Reynauds Syndrome, Ehlers-Danlos Syndrome, my back is broken, I have a spinal cord injury, and there are probably more things wrong with me. Its frustrating. I need to get a car with a trailer  hitch so that I can use the lift that I have. This way I can continue to go to the doctor. I don't care if the car is pretty, has a working radio, etc. I just need an automatic car that my caregiver can drive. She's my sister, she also is disabled and neither of us can afford a payment for a car.

Any suggestions on how to get a car with a severely limited income?