resolution problem

I have a dell d620 laptop with an intel gma 950 graphics adaptor, I recently got a dell 2005fpw monitor and downloaded the driver off the website. trying to get the monitor to run as the secondary monitor hooked up off the vga port on the laptop it gives me a maximum resolution of 1024x768 as opposed to the 1680x1050 supported by the screen. When I first install the driver after reinstalling the uninstalling it it gives me all the standard aspect ratio resolutions up to 1900 by whatever it is. Hower upon attempting to use any of these it reverts back to 640x380 adjustable up to a max of 1024x768. What could I be doing wrong.
I have the screen working fine on my desktop using dvi.