Cheap Ram Overclock

I just finished my first system build, and am absolutely stoked about it. I ran out of money though and can't afford new RAM. I know it's cheap, but my wifes pregnant and she said no. Can anyone help me overclock just my RAM, but leave the rest as is? Is it even worth it? Would overclocking the Northbridge and CPU in addition to the RAM actually make a difference in my case?
I don't often run multiple programs or taxing ones. The most taxing game I have (The Witcher) runs just fine as the system is. I just want things to load and run faster/smoother, and I hate bogging the system with bad RAM. Any Suggestions?

Specs:

OS= Ubuntu 8.04
CPU=q6600
Mobo=NVIDIA nForce 650i SLI ATX
PSU=530W ATX12V V2.2
GPU=2x 8500GT 512mb each (in SLI)
HDD=WD Raptor 74gb and WD Caviar 250GB
Cooling=Air(usually kept below 100f)
RAM=2x CORSAIR ValueSelect 1GB 240-Pin DDR2 SDRAM DDR2 533

P.S. BIOS does not block my access to ram speed and latency.

you can try overclocking your ram in small 10-25mhz increments, untill you dont boot up, then just reset cmos and go back to the step right before you couldnt boot, then use memtest86 to run test on memory. pass all tests once and then you should be set to boot into windows (then i would run prime95 blend tests for at least 4 hours)

overclocking your video cards can increase game performance. but usually you will only see a small increase unless you turn out a massive overclock and its stable. if you do decide to overclock your graphics card use rthdribl program (google it) to stress test your cards at each overclock for at least 2-3 mins to find if you see any artifacts or crashes. also try to find the settings in rthdribl that you can max out like multisampling - i use 16x to stress test to the fullest.

thanks guys, I'll try that tonight