Upgrading graphic card drivers? Monitor issues after upgrade.

So if you've seen my post below - or not - I'm having MAJOR issues with my monitor (Samsung) now that I upgrade from 10.5.6 to 10.6.8. There's distinct distortion as well as my entire desktop doesn't fit on the screen/monitor any longer. I was told by Samsung Tech Support to contact Apple about graphic card upgrades/updates. Anyone know how to resolve this issue? Being a musician and working graphic designer, this is having MAJOR impact on my day to day ability to work and remain productive. Any help would be appreciated.