I'm sorry about your girl.
There is an endless amount of information about liver shunt on YorkieTalk from previous threads. You can use the search function at the top of the screen or the Google search (don't forget to click search on YorkieTalk if you use this one) at the bottom of your screen for lots of good threads.
What tests has she had and how was this diagnosed?
How does the vet know that it isn't MVD (microvascular dysplasia? MVD is small shunting throughout the liver that is inoperable and has to be managed by diet and supplements.
Have you considered switching to Science Diet L/D canned or Royal Canin LS 14 dry food?
If the surgery is successful (about 85% chance), most dogs live long and happy lives. Some places have better success rates than others and there are a few different surgery methods. It appears that the University of Tennessee has the best success rate and uses the best method (closure by ameroid constrictor). This closes the shunt over time instead of all at once, so it is less like that too much pressure will build up. Dr. Tobias at UT has taught other surgeons this method.
What supplements is she on?
The correct diet, supplements and protocol is extremely important for both LS and MVD. If she has surgery, it does not guarantee that there will not be issues afterwards. For the best prognosis, a young dog with an operable shunt should have surgery.
What are her symptoms?