Hello. I am definitely against using any dry food for dogs, and even more so for dogs suffering from kidney problems. Kidney dogs are already dehydrated (almost invariably so), and the long term use of dry foods (even with adequate pre-soaking) causes chronic dehydration to set in.
So, my opinion only ... stop using the dry food.
If you want to try canned kd foods, then that would be fine. Canned versions (for example, Hills kd) have 80% water, so this is an additional way of adding fluids into your dog's systems. More fluids means better flushing of toxins, and less chance of the kidneys further deteriorating.
If you really want to go home cooking, that is possible - and many would recommend it. But I would also suggest you research first. There are certain things you need to do to make sure you aren't causing problems by switching from a balanced kd manufactured food to a home cooked version. The number one priority is to aim for low-phosphorous, low sodium (salt), and high-quality (meaning human-grade) proteins. In stage 3, protein should be restricted to about 20% of any meal.
The link that follows are some of my own recipes, that you may wish to try:
http://www.infobarrel.com/10_Home_Made_Recipes_for_Kidney_Failure_Dogs
I would also urge you to read these two, which are about diet and ingredients for kd dogs:
http://www.infobarrel.com/How_Diet_Affects_Dogs_with_Chronic_Kidney_Disease
http://www.infobarrel.com/Changing_Diet_During_Canine_Kidney_Disease
There are also some supplements worth adding. Pure salmon oil is good for omega-3 fatty acids, but it needs giving with a Vitamin E canine formulated capsule. CoQ10 is also advantageous. Rehmannia 6 or 8 is said to help considerably too. Pre and pro-biotics - such as Azodyl - are said by many owners to help too. Of course, the type of ingredients much depends on blood readings as well as whether they are high or low in certain elements - so never go more than a couple of months without getting a blood test done.
Hope this helps. Feel free to ask any questions you may have.
Tony