|"i love playing fps games like crysis, call of duty, star craft etc"|
Which video card do you have? If you're using the weak onboard graphics, your money would be better spent on a gaming video card.
"so what is my best chance of improving my system using my motherboard?"
I provided a link to the processors supported by your motherboard, it's up to you to pick one. Personally, I refuse to make any recommendation because I think you're making a big mistake investing more money in a system based on an old board.
"my motherboard can't be resell here in my country"
Why can't the board be resold? I understand that a 4-5 yr old board isn't worth very much but what's preventing you from selling it?
"what is your best advice for my pc using my motherboard?"
Keep it as-is. If you're still using the onboard video, invest in a gaming video card, otherwise, hold on to your money until you're ready to replace the motherboard with something more modern. You do NOT have to replace the processor or RAM, you just need a decent board. If you have some sort of "phobia" about overclocking, how about "reclocking"? Your CPU currently runs at 2.4GHz (12 x 200MHz) @ 800MHz FSB. With the right board, you could reclock it to 2.4GHz (6 x 400MHz) @ 1600MHz FSB. 2.4GHz @ 1600MHz FSB is better than 2.9GHz @ 1066MHz FSB.