Setup external monitor thru docking station

[Vikas BN <pandita.debian@gmail.com>]

Hi Folks,

  I have a laptop Dell D610 at office, with an external monitor (dell 1905FP)
  connected through a docking station (DVI port).

  I installed debian sarge from the dvd that i downloaded using jigdo. I then
  did a "dist-upgrade" to sid. 

 I can't seem to drive the external monitor  to a 1280x1024 resolution that it can do.
 The resolution is always at 1024x768@75Hz (which is what the laptop's LCD can do). 
 Is there a sample xorg.conf out there from where i can get some tips on setting up the 
 external monitor at a different resolution.

 System details:
    dell d610 with ATI mobility M24 video card
    external monitor: Dell 1905FP

Thanks,
-vikas