Senior needs transportation

I am a 72 year old with underlying issues like blood pressure, diabetes, and kidney disease among other things.  I  need to be able to get to my medical appointments, but my car is dying.  Rattles and smoke indicate huge damage and unreliable transportation means that it is going to be a problem getting to the various docs that are keeping me going.  
I have a small fixed income from social security and get food stamps to help, but with an income (including the food stamps) of less than $900 per month there is nothing left.  
I need to buy a used car that will keep me going for the next few years.  I can use some of the stimulus money but it is not enough to get a car that is suitable. 
Can you  help? A dollar here and a dollar there will add up and I will be able to get to the doctor.  I am truly grateful for the love and kindness of my children and friends.