Whiskas I cant find any minimum requirements for the usb one from CCL or the D-Link site itself but I found this :
New Support Service:
For technical support for:
Broadband Modems/ Routers
Internet Gateway inc Wirless Gateway
ISDN Routers
Call Freephone:
0800 917 5063
Please call the above number ONLY for the
above listed products
I sugest you give them a ring and check that it will work ok with your PC,(it may be as well to confirm that the PCI one will as well although it seems from the listed specifications that it should).
A PCI card is about the easiest thing to fit yourself in a PC but if you are unsure about it I am sure that Bat would happily fly over and install it for you