Ah, those are overclocked numbers.
By pure chance I did find a way to boost it without overclocking to 184MHash by adding a -v argument to poclbm. Does anyone know what that means and are there more of such arguments? Thats 20% more!
-v tells the miner to work in vectors, which is more efficient on some cards.
-w128 specifies the work size, there will be a "sweet spot" for your card, try adjusting the number (must be a power of two, so w64, w128, w256 are all valid while w99 is not)
agression is... well it's pretty much what it sounds like
I only managed to pull about 18% more with flags alone, the big boost came with overclocking the core clock and underclocking the memory clock, that's what took me from 192 to 277 MH/s