Overclock Help!!!!!

I Want to overclock 5200+ CPU. I hope you can help me.

Here are information about CPU:

CPU: AMD Athlon 64 X2 5200+ Brisbane
(Socket AM2, 65nm)

Cache:
L1 D-Cache 64kb X2
2-way set associative, 64-bit line size

L1 l-Cache -same as above-

L2 Cache 512kb X2
16-way set associative, 64-bit line size

Mainboard: Biostar
Model: NF520-A2 TE 6x.

BIOS:
Brand: Phoenix Technologies, LTD
Version: 6.00 PG
Date: 05/23/2008

Graphic Interface:
Version: PCI-Express
Link Width: X16 - Max Supported x16

Graphic Card:
Model:Ati Radeon 4650 HD 512MB GDDR2 600/800

Memory:
Type: DDR2 Dual
Size: 2x1GB Kingston 800mhz

PSU:400w

OS:Windows 7 32-bit Service pack 1 7601

I'm stuck at 3 ghz(Prime 95 stable) but I would like to get it to 3.1 ghz(Prime 95 stable)!
when I boot up at 3.1 ghz it works great but in prime 95 there are errors and after playing a game(Assasins Creed Brotherhood) for 15-30 minutes it just closes the application .....PLEASE HELP

Personally I would leave it where she stands...All cpu's clock differently some 3.5Ghz some less some more...That .1Ghz is not really gonna mean a lot to be honest

P.S if anything...just by looking at your specs I would guess its the PSU not pushing out enough amps

trust me at 3.1 Ghz works much better than at 3 Ghz!
I thought the PSU is the one that's holding me back but when I did calculations the result was 235-280 watts.....
and I don't know how to raise the CPU voltage, in the BIOS there is CPU Voltage control (it goes from +0.012 to +0.787) but I tried every voltage and CPU-Z shows allways the same (from 1.312 to 1.344)!
can you help me???