Hi there, I'm also a Toshiba laptop user with an ATI X1200--I have a sweet little 15.4-inch Satellite A215. Have you tried the installation instructions at http://en.pardus-wiki.org/Atidrivers
I know they refer to the outdated 8.40 drivers, but these instructions worked fine from me. If you haven't tried doing so yet, take a try at getting the ATI drivers out of the Pardus repository (it's version 8.455.2) and make the suggested modifications to the configuration files. I'm not sure it's actually necessary to turn Composite off anymore.
Sorry that I can't report on 1440*900 resolution with this driver because my laptop's display is only capable of 1280*800.