Router and xbox help?

ok so this isnt my issue but my sisters husbands issue with my router, he has an xbox360 elite, and it was working just fine in out old house where it had 4 walls between it, we moved to out new house and it now only has one wall between it and the router and the router sits on my sub-woofer, no other device has an issue with connection or staying connected, online the xbox, xbox said we need to change the channel on the router, the router is set to auto, and we tried all the other channels, it connects gets great signal, starts to play a game, and drops to 1 bar and goes between 1-3 constantly, is there any way to resolve this issue without having to call xbox again or having to buy a new wifi adapter? oh and the router is a linksys E3000