Sharon...thanks for the reply and advice. Sounds like we are doing most things right for prevention...less the cranberry which I'm going to pick up today.
As for there possibley being something more...I'll ask the Vet if she took a look around when she was in there for her spay. She's been spayed for about two months now, so maybe things will start to get better with time.
As for the antibiotics...I think we were doing 20 days worth maybe, but can't remember because there have been so many different times and issues. I've got a call into the vet for some more so I'll ask about longer and/or something stronger to really try to knock it out.
Thanks again for the suggestions.