I'm pretty sure this is just a regular xbox360 controller, which you can get from any of the gaming stores that sell that kind of stuff [nino... virgin... etc]
If you get the wired version you can plug it in directly and download a driver off Microsoft's site
http://www.microsoft.com/hardware/download/download.aspx?category=gaming
If you get the wireless version you'd also need a wireless receiver thing like this one
http://www.amazon.com/Xbox-Wireless-Gaming-Receiver-Windows-Pc/dp/B000HZFCT2/ref=pd_cp_e_1 - I saw that at nino's a year ago as well.