Well with integrated graphics, the best you can do is change BF3 graphics settings to LOW and turn off all Motion Blur. That should give a decent increase in FPS. Also lower the Resolution to something like 1024 x 768 or even lower. Also disable VSync and Triple Buffering.
I used to have gtx 480 and intel 2-core processor @ 3.4 ghz, and it ran the game at 50 fps
The trick is to scout google for "performance boost" or "performance booster for games", find whichever suits your system, and you may get 10-20 fps increase sometimes, depends on how littered and capable your machine is