You definetley need to add more details for people to give you useful advice. How will the robot move? Are you going to use a microcontroller or not? More details.
Hi ronnoc
The kind of thing you want to make will need an H bridge, without it your robo won't turn, try this first.How to Build a Robot Tutorial - Society of Robots study every part of sensors and H bridge from that link, you'll have a good idea about your robo.