What are good conditioning excerises and food for a gymnast?

I'm a gymnast and I need good conditioning to do for: abs, arms, thighs, ankles and knees(I have really bony ankles and bad knees) and also good toning ones too. I'm also always really hungry but I don't know what are healthy good foods for me to eat!! And am I a healthy weight? I'm 13 5'3"ish and i weigh 108-114 it varies..thanks!!