i have p5g4it-mlx asus motherboard, can it support 2gb hd graphic card

Yes, it can in theory, but if 1) the 2GB HD GPU is pcie2.1 or pcie3.0 2)the ASUS don't have the bios update for the MB then it can't. At this moment, I can't check the support website ( maybe down time), you can check it later. Because your MB has only pcie1.1, here is link amoverclock29 from overclock.net has the answer.

The final answer to the controversial PCIe x16 version compatibility. http://www.overclock.net/a/the-final-answer-to-the-controversial-pcie-x16-version-compatibility
P5G41C-M LX http://www.asus.com/Motherboards/P5G41CM_LX/#support