Here is some info about paying for medical bills:
http://www.yorkietalk.com/forums/sic...vet-bills.html
Many people here have had great experience with Care Credit.
Definitely go to the board certified internist or the university as LJ recommended. They are better equipped to figure this out and to do it efficiently. It is a lot of money, but in the long run it will cost less than trying to work with a regular vet -- and the outcome will likely be much better.
Keeping Lucy and you in my prayers.