too all sifus out there, i'm buying a used laptop for dota.....

what's the minimum gpu that Dota/Warcraft will run like my pc....?

i'm not a hardcore resolution freak, am happy with dota on my old rig
athlon 1.6ghz, 1Gb Ram, GF FX5200, res 1024 X 768 (16bit) or 800X600 (32bit). i'm not fussy.

any ideas? will radeon 9000 be equivalent? or should i be looking at something higher?

thx in advance guys.