Suggest Diet To Reduce Creatinine Level Post Angioplasty

On 16th Feb 2015 my father suffered from heart attack and on next day doctors have done angioplasty because he was having 90% blockage in LCA. I m not sure because of the angioplasty or what his creatinine level was increasing and it has reached to 7.8 but now the creatinine level is going down and as per yesterday blood test it is 6.3.  Those doctors have suggested us to keep a close watch on water intake and urine output and i m doing it. In a whole day i m advised to give only 1.5 ltr water on maximum side. Could you please suggest me food which will help in lowering down the creatinine level. My father s age is 64years. No diabetes, No blood pressure