Officially, I don't think ATI has Mac OS drivers for the HD 4350.
If you are comfortable working in a UNIX environment, and can take the time to convert incompatible driver commands, you could try to manually install ATI's Linux driver using a UNIX shell like Terminal. If you do, post back your results.
There are few kext file available for ati hd 4350 mac os x but they are only applicable from snow leopard onwards. Mac officially supports only ATI 48xx series but the kext i told you are modified kext by some guy called Netkas.