Hello and Welcome to our Community.
I've had a few kidney infections through the years but I just took the antibiotics and ate properly and everything was Fine.
As far as a diet, your Dr. or Dietician should have already told you that information. We do not know if there is something more wrong with your kidneys than just a UTI. You also didn't say if you are Male or Female. A Male obviously would eat more calories or carbohydrates than a Female. You also didn't say if you are over-weight or not.
Here is a typical diet if you need to lose weight. It is only 1200 calories so if you're a Male then you would have to add more of similar foods.
Mayo Clinic Healthy Weight Pyramid: A sample menu - MayoClinic.com
If you are having kidney problems other than a simple Urinary Tract Infection(UTI)then you really should go by the Diet that your Dr. or Dietician recommended.
There are other meals to try in the diet section.
If you just have a normal kidney infection, then the Dr. should test your urine again after you finish the antibiotics to make sure that you are okay.