First of all you will need a microcontroller. There are many threads on SoR about peoples preferences. I use an Axon II but you should choose the microcontroller thats right for you.
I would forget about the bluetooth for now, it will be easy to add later once you are more familiar with programming and robotics.
I would also get a pair of servos (you can opt for motors and a motor controller instead if you prefer). If you buy servos, you will need to purchase continuous rotation servos or modify them yourself.
With servos (or motors + controller) and microcontroller in hand, I would first work on learning how to control the servos for some basic movement. For example: forward, reverse, right, and left. Next I would work on controlling the motors with UART through a USB cable connected to your computer.
Once you are comfortable with this, it would be time to consider wireless control such as with bluetooth.
