I purchased a Laser writer 12/640 PS?

I purchased a Laser Writer 12/640 PS printer and was told That windows would have the driver. I have Windows 7. I turned on the printer and plugged it into the USB port and it showed up as a printer under the listing of (Unidentified) list. I can't seem to move it to the printer list or print any thing on it. Can anyone recommend a fix or what I need to do? I hate to think I wasted my money on it. It seems like a decent work horse for my home office.