Maximum FPS count not going above 60

Thats due to V sync been enabled, it can be disabled in gpu driver settings.

You also take a performance hit when running FRAPS.

I believe the Mobility HD 5870 is a little faster than the desktop HD 5770 (no way near a desktop HD 5870) so take that into consideration.

VSync is enabled. Disable it & your frame rates should go up.

ya right, vsync was enabled ,after disabling it ,a considerable FPS increase is there. but usually what should one do,i mean should i keep vsync and triple buffering on or off . what exactly is the criteria of enabling or disabling vsync. and what kind of effect it had on the graphic card(in the sense putting more pressure on the graphic card)?

I've played both ways, but I have been leaving it off. It depends on the game really. You get better performance if you disable it, but sometimes you will experience graphical clitches with it off.

*glitches, sorry.

It could only mean that you have Vsync on. Since your screen might be 60Hz one, it will not go any further with Vsync on. Try disabling it. Also do you get a constant 60 FPS ?
if you do, don't you think its enough to play any game smooth ?

read above...issues been solved, everything after that has just been bla bla bla

yeah you are right.