Baby feeding syringes or like the one you have without a tip will do. Baby food is easy for this purpose. Try using chicken one (the one that's only chicken and chicken broth with no vegetables) put it in the syringe and force feed some in her. Do small sessions every time. I know this is a stressing experience for her and for you as well however she needs some food or else how will she get a bit stronger right?
Chyna