the links posted by taz have a time out limit thats why you are getting this error.
click this link.
http://www.ati.com/
then click software and drivers.
choose what windows you are running.
that will take you into the newest drivers for your card plus the Knowledge Base.
one thing to note before you update your video card driver.
the new drivers listed at ati need the very lastest version of direct x installed.
make sure you download that first before you go ahead with a driver update.
direct x can be downloaded free from this link.
http://www.microsoft.com/windows/directx/default.mspx