I don't know which miner you are using, but I am using guiminer. There is a spot that says device. Before I updated my ATI driver only the cpu was listed. At first I thought 4 Mh/s was good, (maybe for the cpu it still is). Make sure you have it updated. Because 2Mh/s is really low. Don't expect to get anything with that. Without overclocking my ATI 5770 I get 150-165 Mh/s.
Just to be more specific, if your graphics card isn't appearing, chances are you're missing the AMD APP SDK. If that's the case you can find it at:
http://developer.amd.com/sdks/AMDAPPSDK/downloads/Pages/default.aspx