Suggest Treatment To Start Walking After Liver Transplant Surgery?

I am a male of 69yrs old. due to contemination of blood transfusion i got hep c. in 2011 nov liver transplant at APOLLO D elhi by a a very skilled surgeon I am keeping fine but my problem is I feel hungry and i have started eating too much . I have a wt about 91 kgs , my height is 6.1 , I am fortunate not to have sugar and high BP, I have left eating sugar and fat since my docter advised me not to have and cut down wt eato 78 kgs which looks impossible. My knees are not allowing me to walk,sometime I fall also not keep balance. since I do not live in Delhi It is not possible for me to go delhi often and its expensive also to meet him at Apollo. my doctor is a very kind person but Its my inability i can not go to him. Dear Sir, If you kindly give me some tips so that i start walking and keep balance.with respectful regards, Ravi uppadhyay