Your best bet is to get a 3G router that supports the Novatel U679. You might look into the routers offered by Cradlepoint
which is the company that produces the most highly regarded 3G routers. You will need to check that your modem, used with your carrier, is supported.
If all of your computers connect wirelessly, then you might want to check into software called Connectify
which will let you turn a Win 7 computer with a wireless adapter into a Hotspot in order to share with your other computers.