I'm a bit unsure of what your question is. Can you provide more details?
The board that you linked to on eBay is designed for controlling several stepper motors. It also has some auxiliary inputs and outputs for handling things such as relay controls and limit switches.
There is a lot of info on this site about using that board with Mach3 to control steppers and CNC machines - just do a search on TB6560 to bring up a list of relevant threads.
I'm not completely certain about how you want to control the laser, or whether your question is related to the software aspects or the electronic aspects of that control.
Did you get the laser through eBay as well?