Refresh Rate Problem on Dell I9300 ATI x300

Hello People,
I recently formatted my system and upgraded to Windows Xp professional SP2
(previously winxp home). I have installed all the latest drivers available on dell website.

The default resolution is 1440 x 900 at 60hz which i feel is not right as i have started to get headaches and eye strains. I reckon it was 75hz at same resolution before i formatted.

I have tried several other third party softwares like powerstrip, rivatuner, reforce and catalyst control centre as well to override the refresh rate but nothing seems to work. It just doesnt change.

I am not sure if there is any monitor driver for this screen and it appears default monitor in device manager.

I tried other resolutions but nothing seems to fit in properly.

Is there anyway i can resolve this? any help is appreciated.

Thanks