I am a mom of 3 kids with special needs. 11,10 & 5

My oldest is autistic, has ADHD, interstitial cystitis, scoliosis and low immunoglobulins that keep her sick (They decided she was no longer eligible for disability or SSI when she was 7)... My middle child has ADHD, low immunoglobulins (the more severe type) and Sensory processing disorder along with horrible anxiety. My youngest is severely autistic, was born with hydronophrosis (currently ok), low immunoglobulins levels, and ADHD, he was also born with "curly toe syndrome". 

Recently we are down to 1 vehicle for 7 people. This includes my parents who are also disabled whose vehicle also went down. So everything falls on me. The vehicle we do have is 19 years old and is falling apart. We currently have no AC so my babies are riding around in a car with almost 300,000 miles and no AC. 

I cannot work because I am all of their care takers. I am constantly running from school to therapies, doctors for both them and my parents and am stretched so very thin. I'm behind on bills because every month or so I am fixing the AC in the vehicle we have. 

I just need a little room to breathe. I hate having them suffer through this heat. A Simple ride from school to home has them pouring sweat. I am 32 years old and I am beginning to believe I wasn't built strong enough for this. I am trying my best. My best just doesn't seem to be good enough. 

I am not looking to get anything special. Just something that will fit a car seat and all of them at once. Something that is reliable and has air conditioning. 

Anything would help. Thank you for your time.