I am so sorry your dog has been diagnosed with high kidney levels. Did your vet tell you what the numbers (BUN, creatinine, phosphorous) were? The staging of CRF (chronic renal failure) is based on the current creatinine levels. You can find information on staging of kidney disease at this link and there is a chart at the bottom of the page that is pretty easy to understand.
01 Kidney Failure: Where to Begin - VeterinaryPartner.com - a VIN company!
There is also a lot of information, including a section on Azodyl, on the dogaware site.
DogAware.com Health: Kidney Disease in Dogs
Every dog is different and responds differently to treatment, so it really depends on your dog and what the numbers are as to how quickly your dog will respond or if just adding azodyl and changing the diet will be enough treatment to get a positive response. Azodyl is a pretty controversial treatment. Some people swear by it for their dogs and say it really helps, some say it did nothing for their dogs, and I've heard others say it causes nausea in their dogs. It is quite an expensive supplement, but if it works for your particular dog it's worth every dime. My yorkie was diagnosed with kidney disease almost two years ago, and has been on Azodyl since shortly after his diagnosis. Honestly, I can't say whether it's been beneficial for him or not, but what I can say is that after two years he is still chugging along and his numbers dropped and have stayed low, so the combination of Azodyl plus other interventions is working for him.
If your dog's numbers are very high and he is not responding to the current treatment, s/he may need a course of IV fluids at your vet's office to get the toxins flushed out of his system, and that is often followed up with subcutaneous fluids (fluids injected under the skin and usually done by you at home). Again, it really depends on your dog's response to treatment. My little guy has been getting daily fluids at home for over a year now. He gets just a small bolus of fluids every morning (100 ml) which takes me about five minutes to administer, and it keeps him happy, eating well and active.
Unfortunately there is no cure for CRF and it is usually progressive, so the goal is to slow or stop the progression of the disease for as long as possible while maintaining the quality of your dog's life. You will find a lot of information on that dogaware site, so click through the links and read, read, read.
Hope this helps.
Diana and Scooby