How to update ati drivers on Ubuntu
Yes, you can go to hardware center and just pick the drivers ubuntu finds for you. I just tend to like manually installing Catalyst from ati. To do so, go to http://support.amd.com/us/gpudownload/Pages/index.aspx and download the drivers for your graphic card. Then save it, go to the folder in terminal and type:
sudo sh ati<tab>
<tab> meaning press the tab key to autocomplete the file name since I am not sure which version you got. Now you should have the latest version of Catalyst and drivers running on your system. Got to love ATI for Ubuntu. Worked perfectly for my radeon hd 4870.
Now if you want to configure it, open terminal window and type: