Driver editing under linux kubuntu

Hy,
I need help with editing a driver of a wireless lan card (on pcmcia). I installed Kubunt and from installation point it installed the module it needs to run on wlan. It works fine, but i need to edit the driver, for a project. I don't know how to do that. I red some kernel programming docu, and some about LKMs, but i still don't know where to find the sources of the current driver (the one in use). I looked in /usr/include/linux/wireless.h and seems interesting, but it uses this parameter dev that it says it's the handler to the driver.
Could anybody help me?

Thank you in advance.