I am a day late already here. Your dog, I hope is feeling better by now? And/or you took her to the vet ?
The main danger with vomiting and diarrhea is dehydration, which can be dangerous for a dog. Usually a dog who has been ill like that for more than a day or so will need a fluid IV.
If they feel sick and can't eat, most often they won't drink, or the water will come back up, so an IV is the only answer, unless regular small amounts of some fluids such as Pedialyte, or water with a little honey dissolved, will stay down.
Sometimes a badly upset tummy will recover in a day or two with resting the digestive system (i.e. complete fasting for 24 hours, except for small amounts of fluids.)
When the dog starts to look a little better, the best food to try is plain boiled rice to start with....small amounts every couple of hours. If that stays down and the dog improves, add some plain boiled chicken or white fish (no bones!) Feed that for the next day or so, gradually re-introducing their normal food.
Usually unless there is a serious condition, an upset tummy will right itself if treated like that.
But a vet's advice is always the best thing, so either take her in, or call your vet and ask for advice.