System requirements for far cry 2 are not that high but I doubt you will get ultra
Download MSI Afterburner.
Move core clock slider higher
Run kombuster, if you have problems reduce the clock speed.
Look up overclocking on other threads.
If you ignore heat problems, mobile gpu's can usually overclock quite well.
My old gt 525m overclocked from 600 core to 750 core. ~25%.