Help Buster Get MRI And Surgery

Buster is our lovable 14 lb rescue dog we saved 4 years ago from a very neglectful and abusive home. He's playful, lovable, and everyone who comes in contact with him falls in love immediately. Unfortunately Buster had an accident and was in pain and having trouble moving around and couldn't even jump up onto the couch or walk up stairs. We rushed him to an emergency vet here in Fremont and after a brief consultation the determined he might have a strained back. They gave him a pain injection and 2 pain med prescriptions. The vet did mention that if there is a slipped or herniated disc he might have some nerve issues. We brought him home and he seemed woozy from the medication and unstable. When he was in the vet's office his movements and walking were slow but he seemed normal. As the night went on we noticed he seemed slower (again we thought it was just the meds). When we woke up this morning tho it was as if someone replaced him with another dog. His hind legs were not working and could not support his weight anymore. He was dragging his legs behind him as he tried desperately to walk. He seemed confused as if he was wondering why weren't they working. 
I have been checking with Buster's vet and his diagnosis is a possible Intervertebral herniated disc and a CT scan costs around $1,200-$1,500 and back surgery is estimated between $6,000-$10,000 and if the parallysis does not go away there will have to be aftercare (i.g. doggie wheel-chair and physical therapy). 
We are not a wealthy family and I was ill preparred for an emergency like this. Buster is my daughter's baby. He is such a sweet part of our family. Taking walks outside is one of the only things that Buster loves doing and this problem is causing him to not walk at all. I'm beside myself with saddness and anxiety worrying about how I will be able to get this urgent surgery for him. The longer we wait the less likely he may ever be able to walk again. This is killing me inside knowing I can't afford to get him the necessary emergency treatment. 
Please help our sweet boy.