...is the firts thing needed!
If that turn out to be impossible, firts thing to do is rehydrated her as soon as possible, give them fluids? ( my english ). Go to the drugstore and get a bottle of fluid , sure they will tell you how touse it.

Second , try to make her eat some food ,
Royal Canin have new crunchies for kittys , BABYCAT 34 , specially made for kittens from 1 months to 4 months. Pericot my new kitty love it , it says that have nutrients to help the inmune system. They are higly digestive , you can even soak it in water to melt it and feed her with a serynge. She needs desesperately tho gain strengh ,to fight for her live ,right away.

Good luck Crush, hang on there!!! We want to see you here on board !!
I'm on the Cinder&Smoke prayer line....