d-link usb adapter+at&t 2wire dsl

how do i get my d-link dwa-140 rangebooster n usb adapter to get internet from my at&t 2wire 2701hg-b dsl modem/router with wireless?

i find the network with the d-link, give the WEP and seem to connect to it, but i get no internet, no ip etc….

help! 🙂

Thanks,
Rick