Is my AT&T U-verse RG flaking out on the wireless end?

My son has reported that his gaming will occasionally hang for 20-30 seconds, which is long enough for the WOW server to boot him out. He said this never happened when we had the Linksys router and has only started since the switch to AT&T U-verse from Comcast. He is on the 2nd floor, which is 2 floors above the RG/router. His signal strength is excellent, so it's very likely a product of the wireless fuctionality of the Residential Gateway (RG). He is the only heavy user of the wireless network (I have several devices, but he gives it the biggest workout...BY FAR). In any case, my old Linksys router is just sitting in a box, so I found this site that explains how to use a Linksys WRT54G as an access point instead of a router. I changed the channel the RG wireless is using to see if that helps, but if the hangs continue, I will put the Linksys back into service, utilizing my WRT54G as an access point (and disable wireless on the RG).