That's Charlize 3.2, rendered with RealWorld 2.005. The hair comes with the model, but its shaders and morphs have been adjusted for the render :)

All kidding aside, it is possible to attain similar results with Poser alone, but it will take alot of practice to be able to do so. Buying realism kits and poses and this and that aren't always the best way to learn. The realism kits would be a good investment, but only if you are willing to actually go into the Material Room after applying one of them and study/tweak the settings.