Help Diamond get an MRI

Diamond is the love of my life. She's a great companion. Doesn't ask for alot only love and treats which she gets ALOT of. I took her to the vet because she was throwing up and not eating. The vet did an x-ray and found a tiny bone in her colon. She hasn't and won't eat and it's been almost 2 weeks! I took her back today thinking this bone was making her feel and act this way but it's much more serious. She can't walk, barely holds her head up and she doesn't eat or poop or urinate. The vet says she needs an MRI to rule out a tumor. They don't know what's wrong with her only that its neurological. She's not old so it's not time for her to leave me. I've spoken with the specialist and to walk in the door is $100. The MRI is $135. If anyone could help, please help my baby!