The wifi signal strength on the 3800HGV is horrible - I start losing bars within 15 feet of the router, and have no signal within 30-ft. It didn't matter what I did with any of the settings.
With my old set-up (prior to uverse), I had an older Linksys router which I had installed DDWRT. I set-up the router as a wireless access point, and just plug it into the back of the 2wire router. I now have excellent signal strength within 75-100 feet of the access point.
Important hints when setting this up - follow the instructions on the DDWRT website, use different wireless network names for the 2wire router and the access point, and give the access point an ip address far from that of the router (i.e. if the router is 220.127.116.11, the access point should be something like 18.104.22.168).
The IP doesn't need to be far away, just different. I like going 1 off as it makes it easy to find/remember later when a WPA key or SSID needs to be changed. If you do go far off (or even if you don't) I highly recommend writing it down on some tape or something attached to the access point so you can find it easily 6+ months from now.