Graphics Cards help

I recently bot both MEs for Pc (I have them for xbox as well and I have my reasons) but I need to update my graphics card as the one I have at the moment I am unable to play ME and the Graphics are none existint in ME2. So I am asking for help to which kind of graphics card I should get, as I dont want to get one and when ME3 comes out find I need to get an other one. A graphic card that I thought of getting was, XFX AMD Radeon HD 6870 PCI-E Graphics Card - 1GB, but is this good enough.