A mobo upgrade is point-blank cuz it will NOT boost your FPS by 10/20/100, etc. It will perform more or less the same as your current one with the same cpu & gpu. A gpu upgrade will DEFO boost your FPS.
The T-Force is an overclocker capable of pushing AM2+ BE's. Keep the mobo. Save up & wait for AM3.
i would say yes. 2 GPU is really data hungry. people usually OC their Intel to 3.4Ghz and above. so clock for clock AMD will need about 3.6Ghz to do the good job. i mean test it out with Fraps see how much fps you will gain when you OC from stock to say 3.2ghz.