KD is a prescription food you get from the vet - it's formulated for kidney failure. We found out that our Kiki has kidney failure in the Spring and have been giving her subcutaneous fluids every other day along with the kd food with supplements. There is a yahoo list for cat's in renal failure - it's full of helpful info. In fact just about any question you have, someone there can answer.
I'm sorry you have to deal with this - it's hard, but apparently they can hang on for quite a while with the proper care! You can pm me if you'd like.