Deus Ex Human Revolution is the first major game to support AMDs version of 3d. Crysis 2 uses nVidias implementation. If you want to see Crysis 2 in 3d you need to switch to an nVidia card, get nVidias funky glasses, and get one of their certified 3d monitors.
It's an investment. Perhaps Crytek will add support for AMDs 3D implementation later on, but for now your SOL.