I'm so sorry your having to deal with such a difficult situation such as this.......My Jack, who is 5, was recently diagnosed with this too.....Most vets will typically send you home with prescription food and tell you good luck. I found the most helpful advise from these two sites.......
DogAware.com Health: Kidney Disease in Dogs
This one you have to join.....
K9KIDNEYS : for owners of dogs with Kidney Disease
There is no way to determine how much time we have once they give this diagnosis. Some will live quite well for several years, and sadly some won't. Everyone is different. Once you start reading you will see there are many things you can do to try and slow the process down. We all have to decide for ourselves how much we are willing and how much we can do......
There is the diet, a lot of dogs won't eat the prescription food, so a lot of people will home cook. That is where the K9 forum will/can help you. Phosphorous is detrimental to the kidneys, there are phosphorous binders that can be add to the food to help with this.
There's also supplements such as fish oil, vit. E, & coq10 to help with the kidneys. There are B vitamins, that are lost from the urine output, which can be helpful to them.
There are sub.q fluids you can do at home to help keep them hydrated and to help flush out toxins. If you have a nephrologist in your area they may be better able to advise you in Rockybears illness. I don't have any in my area so I just have the regular vet......
I know this is a lot to digest. I'm still in the figuring out process. All I can say is to do as much reading as you can and don't be afraid to ask questions on the forum.....Good luck to you and I wish you and Rockybear well...