Benson is in need of medical care

My sweet boy, Benson is in need of medical help.  He is having difficulty holding himself up and walking. I have taken taken him to the vet, had xrays and is on several medications.  It has been a month and he is not getting better. Today the vet told me to increase his meds and come back next week. She said at that time if he's not any better she's going to refer me to get an MRI and possible surgery. She says it could be  one of two things he could have a disc in his neck that might be trying  to blow or a tumor. If it's the disc he can have surgery they can go in and clean it out and hopfilly he'll be all better.  She said there's not much they can do about a tumor.  But we don't know unless I can get the MRI done. She gave me an estimated cost of $3,000 for the MRI. And if he has to have surgery it could be 7 or $8,000.  PLEASE HELP MY BENSON!!
Any money over the amount of his medical bills will be donated to the local animal shelter.