That all sounds very scary, I'm sorry
I hope your baby will be allright, though I'd be changing vets if this was my little one. $1,000 just for basic exams and bloodwork, and they continue to let her suffer like this? Insane!!!!!! If you cannot afford to properly care for her, please consider surrendering her to a rescue. Continuing to let this vet guess at it is not going to help her. Liver Shunt should have been the first thought he had and immediate testing and treatment begun.
I hope she'll be okay.