It's probably best to speak to the vet who performed the surgery. It can be slow going. How much of the intestines were lost can also be a factor. If a lot of her intestines were killed off it will take longer and you may need to make some changes permanently. Sometimes they need some mild antibiotics (you can speak to them about tylan or something if needed) or just need probiotics to help depending on whether there is a case of too much or not enough. Are you still slowly reintroducing food? Maybe when she's vomiting it's after eating a little more or something? Do things seem well during rechecks? Your best bet is to call and speak to them any time you have a question as they are familiar with her case specifically and have her records. I hope things are okay and she's back to normal soon.