Try to figure out if your area is served by VDSL2 or ADSL2+. You should be able to tell what type you're on by the modem they provided you. http://en.wikipedia.org/wiki/AT%26T_U-verse
If you're on VDSL2 you're totally fucked. If you're on ADSL2+ you "can" call att, get them to switch you off of interleaved and onto fastpath. That SHOULD improve your ping. You will have to jump through hoops like never before to get it done. IIRC 800-288-2020 is the tier2 support number. You could also try the ATT direct forum on dslreports, they're much more helpful than calling customer support.
For those in the greater bay area consider switching to sonic.net fusion. They provide bonded ADSL over att lines with better pricing for the speed. I have heard nothing but good reviews about them. Shame my area was too far from their CO.