Go to www.driverheaven.net
and download Mobility Modder. Then go to www.ati.com
and download the latest Cats. Install the Cats. You'll be told that your card isn't supported. Run Mobility Modder, point it to the folder that contains the Catalyst files and let it moddify the inf files. Rerun the setup. Reboot. Your now using the latest ATI drivers.
Your mileage may vary here as several of the posters in the driverheaven forums have had issues with the way mobility modder modifies the latest catalyst drivers but it's worth a shot. FWIW I couldn't get the 5.4 Cats with CCC working properly but have had really good luck with all the other versions.