Stop trying different brands. Pick one good, nutritious food and stick with it. Stop giving her anything else - especially people food. It's not good for her, healthwise, and it's a bad habit anyway. How old is she? If she's a pup, pick one puppy food and use that for treats and for meals.

I would not worry about her throwing up once, especially with all the confusion her tummy must be going through right now. If she throws up a lot, a trip to the vet is in order - has she seen a vet yet?

She's in a new situation, and now is the time to establish good habits, foodwise and otherwise!