Try overclocking the Core Clock of the card a bit more, I found with my 7970 that beyond ~1450Mhz on the mem clock performance actually decreases (according to 3D Mark 11 Basic). Being a 7970, it can overclock much further.
1200Mhz on the Core, 1575Mhz on the memory.
Voltage I wont tell you doing so is pointless, no two cards react to voltage equally so you will need different voltages to hold the overclock.
I also did a 3DMark Basic run through, this is the score I got. Settings are easy as its the free version, cant change them at all. http://www.3dmark.com/3dm/670879
Core clock for the card comes in at 925Mhz, suspect thats because it checked while the card was idling, but its definitely at 1200Mhz during the test.
You can make Catalyst Control Center update itself, but I just manually download the latest driver. http://support.amd.com/us/gpudownload/Pages/index.aspx
Punch in the right things, download the latest driver (or the Beta, but obviously isnt guaranteed to work 100%) and install it. Upgrading from Catalyst 9 to 13 will give you a fair bit of a performance boost, Catalyst 12.11 was a fairly big update to performance across the 7000 series.