Pretty decent rig and Batman is a terribly coded game so it will run worse than any other game. They need a patch.
If you still want to upgrade, I would keep the RAM and GPU and save money for Ivy Bridge and get like a 3770K and a Z77 / Z75 mobo. (Z75 = no SRT if you don't have a SSD)
i love to get that CPU too, but i think that 3770 still hardly to find here in Malaysia @ too pricey. the SSD thing maybe will be in my list..