Hello, it is known by now that there are several performance issues, even on very high-end pc-rigs. You are not alone. Check some other threads about it here. Also, report what settings you are using. Keep in mind that your graphics card is average, so don't expect too much.
As I see it after reading many posts, the best we can hope for is that Crytek will focus on performance patches. Unfortunately, Crytek does not have a good record on performances patches, so don't get your hopes up too high.
We know Crytek is busy with MP in the first place, and getting DLC ready.