I am teaching myself robotics

I am teaching myself robotics and will like to build a humanoid life size robot. I want a robot to sit down or walk with and talk. I want to take it with me to comic book conventions. I brought a small bi pedal kit and a hand kit. I want it be similar to C3-P0 from Star Wars. I am planning on using a series of rechargeable batteries and build a special charging station for it charge where I will have it stand against the wall or have it as a chair next to an outlet.