I know there might be no chance of this but could you personally talk with the pet store manager/owner? Show them the vet results of her tests. If she gets return there is a 99.9% that no one will get her surgery and she might die. You bought what you thought was a healthy pet. Your pet is now sick,they might be able to give you some money back. It doesn't hurt to go in person and show up with all your vet tests.
It's the same as having a child. No one expects to give birth to a sick child but it happens sometimes and most people can't afford treatment if they get diagnosed with something like this.
I totally understand how you don't have the heart to return her like you would a damaged radio etc.. That's exactly what petshops expect. Has your vet started her on a low protein diet and Marin or Denosyl? Both those meds help the liver work to flush out the toxins. Having a yorkie with L/S is very stressful. My yorkie has the liver shunt that can be controlled with diet . He turns 4 yrs old in March and doing well on the diet ( Hill's Science diet L/D can food)
I was going to suggest the Care Credit card but I just read that it was denied
I had to use it for a $1,300 surgery just to see if he had a shunt that could be repaired . I agree with some here that $2,400-$2,600 is a bit expensive. In florida it cost around $1,500
I wish I could help. The last option ,it's better than giving her back to the store. Would be to give her up to a Yorkie Rescue that will raise the money to get her surgery.At least she will get her surgery that she needs.
Again , I'm really so sorry to read this sad news.I know how much you must love her already in this short time you've had her.
Genie
Cookie
Lola
Angel