Your CPU is the bottleneck.
You'll get much better scores if you overclock your CPU to 2.93 Ghz (11 multiplier X 266 fsb). The faster bus will boost your scores by around 15% if not more.
CPU's Temp is between 37 - 40
I don't think I can overclock my processor with this Temperature
Maybe i should buy a better processor
What do you think of Core 2 Duo E8400? is it good with games?
and do you think i should upgrade my ram to 4 GB? or 2 GB is enough?