First let me say Get a NEW vet! Most vets will take an animal that is vomiting right away. Why don't you try a ER Vet Hospital. Your cat NEEDS to see a VET TODAY not on Tuesday.
PS...DO NOT feed Cats milk. It can give them Diarria. Which will lead to dehyration...she is probably already dehyrated since she was vomiting. She will proabably have to be on IV fliuds.