Workout Regimen for in shape hackers

I've been working out for the past 3 months now and have made some progress but want to gain more muscle. My current regimen is 120 crunches, 100 push ups, and 40 chin ups 5 times a week as well as 50 body squats 3 times a week for legs. Can any one suggest any improvements for my regimen? I've also been thinking of using creatine what do you guys think? Thanks!