I'm with Jan, what kind of vet is it that doesn't know of anything to be given for a UTI? Antibiotics are the normal prescribed medication and usually work quite quickly and should totally eliminate the UTI if all of them are given as prescribed.

Like Jan said, when Tubby had a UTI he was dribbling and left a nice bloody urine spot on the Vet's counter as evidence. UTI's are quite painful and are treatable so if you notice Gidget "acting up" again, take her immediately to a different vet than this last one and I'm almost positive you will get a completely different story.