If she is vomiting brown liquid that looks or smells like fecal matter, you may have an emergency on your hands. This is one of the most common symptoms of an intestinal obstruction so go ahead and see the vet with her right away.
The vet can do a simple x-ray that is not very expensive and rule this out (or in!).
But I do suggest a vet visit as soon as you are able.
Let me know if you want to discuss this more.
