When passing your full system's specs, list them like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
Chassis:
PSU:
OS:
Monitor(and it's resolution):
^ Being as specific as possible.
Simple answer, the performance boost will not be by much, minuscule if anything. I played on BF3 with an Intel Q9550 with a mild overclock+HD6870 with also a mid range overclock and I achieved playable frame rates at 1080p with high settings. We're dealing with two Dual Core processors here with a slight bump in frequency and cache. If you got something like a a Q6600 or a Q9550 then that would be a significant upgrade from what you currently have.
Contrary to what has been said, you can't overclock on that Intel board since it's got safeguards implemented within the BIOS. I don't recommend software based overclocked or using setFSB for tampering with the clocks. The board also lacks the proper heatsinks over it's power delivery area to maintain an overclock (if you somehow managed it). On that note, Intel boards are notorious for being picky with what ram/ram kits you drop into the board. So in this regard, buy a kit and if possible matching it with the memory QVL of the board.
If you want to drop in a new processor, you will need to reinstall your OS. On that note, you should keep in mind that the 32bit architecture of Windows' OS environment allows for a maximum usage of 3.5GB while a 64bit architecture will allow for above 4GB usage by the OS.