Can anyone tell me my ram timings from this picture??

Click the memory tab and post it. The SPD tab shows the timings table and corresponding voltage from the module in slot #2.

ok...memory tab says 6-6-6-18, but i can set 5-5-5-15 from bios.i havent tried anything lower than that.Now my qus is-

1. Would going lower improve performance?
2. How is it goin to affect my overclocking? would reducing the timing cycle limit my clockings?

6-6-6-18 at 400MHz is the best that they can achieve. You could try 5-5-5-15 at 400MHz, but you'll have to increase the voltage to 1.95V or 2.0V. If you leave the voltage at 1.8V, your system will crash. If I were you I'd leave them as is. If you overclock, just make sure that they run at or below 800MHz.

ok im not touching them...i guess i made the wrong buy, i should have gone with ones with lower timings..are the performance difference noticable anyways?and i got a good deal for a ram 2gb 800mhz with 5-5-5-15 timing....now if i add that one, can i set its timings to match with my old one? wud it cause problems?

Since your timings are already set to 6-6-6-18, you shouldn't need to do anything.