For other signs to watch for that may indicate a URI getting worse, look for sneezing, going off her food, lethargy, and noisy breathing (as if she has fluid in her lungs). If you see any of that, I agree with bumping the vet visit up to an emergency if possible, since URIs can quickly turn into pneumonia. I would also guess allergies though, if she just has a runny nose and no sneezing. Hopefully that's all it is!
~*~*~ Kelsey ~*~*~
RIP my sweet Lily ~ 6/12/08 - 1/20/12