I don't know what 2Wire HG you have but in my experience the 3800 sucked especially for WiFi. Your options include:
Setting up a router behind the 2Wire, which may or may not work well. I never got it to work quite right in my setup. The 3800 did not offer a true bridge mode, and I'm not sure if any of their other products do too.
Setting up an Access Point, which is pretty much the WiFi part of a router. It could be put up anywhere you can put ethernet and power. Devices access it, it is connected to the 2Wire and it should work better as long as it's a decent one. Make sure you can disable the 2Wire's WiFi first, especially if they are on the same band (i.e. 2.4GHz).
Move the 2Wire around the house, but not always feasible and it could cause low signal in other areas. You could also try seeing if mounting it to the wall helps. And try to keep it outside of any cabinets/drawers. Having it inside of something will cause some signal loss.