Building a robot with roboteq controller

I would like to build a robot using roboteq controller. I will be using 4x 4v wheelchair motors.
I would like implement two usage.
1. skid steering 4 wheel drive with left/right turn
I would like to be able to control the robot using WIFI with onboard computer with a USB joystick.
Please let me know what type of controller do I need and how can I accomplish the USB joystick controller.

You should be able to take most of the information from
dev.roboteq.com/dev1/robotics-motion-con...-design-instructions
The AX2500 would be the recommended choice but you may be able to use a lower power product depending on your actual motor's consumption and robotweight.
You may consider using a low cost Atom motherboard on the robot side.
On the operator side, our free Roborun utility will accept a USB joystick.