Need help with MRI and maybe surgery costs

Kyla is a 12 year old German Shepherd dog that was very active and energetic up until recently.  Within the last four weeks, she's gone from running around and jumping everywhere to having difficulty even taking her usual walks around the neighborhood.  While walking she's wobbled from left to right, dragged her back feet, and even lost strength in her hind legs.   At first we were told she had the beginning stages of Degenerative Myleopathy, but after a visit to a neurologist they have all but ruled that out.  What they currently believe is that there is some more direct neurological issue affecting her balance and that only an MRI will be able to tell us the exact cause.   We've been told that possible causes are:

-A cyst or tumor on her brain or spine
-Past damage from a stroke or brain and/or spinal infection
-Some other cause that has not been found

The MRI alone is well out of our budget, and if Kyla requires surgery to have something removed or corrected, then I'm not sure we could even afford to have it done.  Any funds donated will be used to cover additional doctor's visits, any and all testing that needs to be done including the MRI, and surgical procedures if necessary to correct the issue.  There may also be a need to purchase items for the house and car to assist her in and out of certain areas without risking a fall and further injury due to balance problems.

She's been our furbaby for the last 12+ years now and while we know she wasn't going to be with us forever, we want to make sure she's around as long as she can be and make it as easy as possible for her so anything you can spare is very much appreciated!