Need help modeling the Koolaid-Man

Ok I found this image of the kool-aid man. And I tried to model him out by tracing him, ok so I’m now done with it but thier is 1 little problem. How do I turn a flat object into a 3-D object. So I can do all the texturing and everything, I’m running Blender version 2.46. Who ever helps me THANK YOU VERY MUCH!

P.S. Plus how do I move the body, legs, and arms.