|Well does the 2wire modem/router have any wireless capability?|
How many LAN ports does it have and are you certain it is a combination modem/router and not just a modem?
Does your new desktop system also have an inbuilt 10/100 network card with rj45 LAN port? Will be very surprised if it doesn't.
Will it be close enough to the router to connect by cable or will it be used in a different room?
In order to get accurate answers to your questions you need to give a complete description of your problem including make/model numbers of the equipment and in this case the environment in which you want the thing to work.
Goin' Fishin' (Some day)