If you can't find the driver you may want to look at some of the digital I/O boards, if what you're looking for is TTL lines. Here's one I found for under 400: http://sine.ni.com/apps/we/nioc.vp?lang=US&pc=mn&cid=3591
To find all digital boards:
http://sine.ni.com/apps/we/nioc.vp?lang=US&pc=form&cid=1103
With this approach, since you're not using GPIB but using the PCI bus on the PC you should get better data transfer throuput as well. This really depends on your application needs on weather it's an issue or not ... and you'll have the LabVIEW VIs that come with the NI-DAQ driver.
Best of luck,
Kamran - NI