I'm not that experienced with this stuff but I think you need a PCI DVR Card.
See >
http://www.sctltd.co.uk/acatalog/GeovisionPCDVR.htmlDepending on the connection coming from the CCTV there are a few different types.
Easiest I guess would be to get a DVR PCI Card that accepts the Ariel type plugs then get CCTV cameras that use that type also.