There is some cleaning stuff that works really, really well at stain removal. The one I used was called 'Out' but there are others. They're available at pet stores for removal of animal related stains. They contain active enzymes that 'eat' organic matter....totally fine to use with kids in the house. I've used these forever. It actually worked on a red wine stain that had been in my carpet for years. Once you get your stains out, get yourself an area rug to use whilst she's still having her belly issues. Sounds like she's got reflux and is a 'happy spitter'....went through this with my nephew. Don't worry, it'll pass