Hello Jamie.....I'm so sorry your little one has been diagnosed with this terrible condition. I have also been given this news recently....This site has a lot of helpful info, it might be very useful and help explain some things the vet can't......
DogAware.com Health: Kidney Disease in Dogs
The vet probably can't give a time frame because this disease effects each pet differently. Some have kidneys that hang in there longer than others. There really is no drugs for *kidney failure* but there are supplements and drugs for the complications that come with this disease. I hope the IV flush brings her numbers down......Good luck and I wish you both well.....