Sounds like you've had a tough time and unless you take serious action, things will continue getting worse.
I'd start with diet. Arteriosclorosis, high blood pressure, diabetes are all interelated ailments that stress the kidneys. The best attack is to control the diabetes and blood pressure through a strict "low glycemic load" diet. Read up on this concept and eat mostly low glycemic foods.
Substitute good fats for bad fats. No transfats, minimal animal fats, plenty of good fatty acids from molecularly distilled fish oil, flax oil, olive oil, avocados, etc. 30% of your diet should be GOOD FAT.
Make sure you get at least 40gm of fiber EVERY DAY, 50% insoluble, 50% soluble. Soluble fiber helps keep cholesterol out of the blood. Insoluble fiber makes you feel full and moves wastes through more quickly.
Lower protein intake to relieve stress on the kidneys. Increase Magnesium intake, since weak kidneys don't preserve Mg. Increase potassium intake, since the salt/potassium balance is more important than the absolute quantity of salt. These are key minerals for organ function.
Eat as many "above ground" veggies as you can. Then eat some more. Have a BIG salad before lunch and dinner. Have veggie snacks between meals. Drink veggie juices.
Have an apple or orange 1/2 hour before each meal. That will help your digestion and lower your hunger levels.
Eat Irish oatmeal for breakfast -- not quick cooked or instant oatmeal. Cook it with 1/4 tsp cinnamon. Sprinkle it with fresh ground flax seeds to add good fats and more fiber.
If you need sweetener, use xylitol or stevia -- as little as possible.
As you clean up your diet, monitor your blood Sugar
levels. Hopefully you can reduce your medications gradually. As you get healthier, you might consider a veggie juice fast to cleanse your body. You'll know better as you recover.
Final note: start walking, even if it is only 1/2 block before you turn around, do a bit morning and evening. Walk a little more every day. Swing your arms widely from the shoulders, and walk as vigorously as you can. Consider getting walking poles to help your balance, reduce stress on the joints and to increase the upper body workout from walking. http://walking.about.com/od/poles/
This isn't easy, but it can make a huge difference. My mom is in a similar situation, though she had heart attacks and angioplasty, not the triple by-pass. Her health has stabilized remarkably when she got serious about a diet like the one I described above. She did it for my dad's medical condition, not her own, but it has helped both of them radically improve their health prognosis. My 80 year old parents look cute striding down the block with their twin walking poles!