That's so sad!! My dad's dog just recently died of kidney failure, we had to put him down the day before christmas eve, because he was declining so rapidly. He'd gotten into some antifreeze without us knowing and once he started showing signs of it, it was too late.
Reading this just sort of reminded me of him. I hope that your little Priscilla pulls through to live a few more happy years with you! She looks like such a sweet cat.
Now we have this big can of Royal Canin dog food to get rid of, and (I dont' think this is bad, is it?) I've been giving little bits of it to Clover and Echo as treats and christmas dinner to get rid of it. We also still have a big box of IV fluids and such that we're needing to return to the vet.
Do you know how her kidneys failed? Was is just a random event? Or did something happen that would make them fail suddenly like that?
But yeah, I hope she pulls through to spend more years with her loving and caring meowmie, and I bet with your love and care she has a good chance of it!