Hi, how long have you had your cat? Could it just be that she is stressed and still needs time to settle in? When I got my cats from the Cats Protection, it took a good couple of weeks for them to feel at home, it may be that she is still finding her feet and will be more prepared to eat properly once she is more settled. If it is not this, then it could be that she is simply fussy. One of my cats also does not like to eat much cat food, she mostly eats the gravy or jelly from the food and leaves the lumps of meat dry in the bowl. She will eat some dry food, and drinks water. She has been like this for years and has managed to survive for nearly 16 years!
If your cat is eating new food at the first offering, then turns her nose up at the second, then it could be that she is spoiled and has been used to eating what she wants when she wants it. You could try putting down some food and then if she does not eat it, clear it away and don't offer any other food until the next feeding time, hopefully she will soon starting eating once she realises that nothing else will be on offer, until her next mealtime.
I take it the vet has checked her teeth to ensure that she has no gum problems or any other problems that will stop her eating?
Hopefully this will be a short term problem that you will resolve once you get to know her better, best of luck. Sue