Gina, I want to second Medusa. CRF (chronic renal failure) is no longer an immediate death sentence. Many kitties can survive for years with sub-Q fluids and the right diet.
PT cats who survived for many years are Catsnclay's Yoshi and T&P'mom's Tubby.

And I hope my Filou.

There is a very good website. Here it is:
http://www.felinecrf.org/

Don't give up hope. After this diagnosis I would rather have some hope!