Yeah, this sounds just about right.  In theory if you supply more voltage this card should be able to hit 1200 core, if you can cool it   I'm thinking about taking one of my cards out of the production rig and seeing just how far I can push it.  350 Mhash/s seems just -barely- doable, but would be horrendous for juice and cooling.

I'm also using 2.1 and poclbm, haven't had enough time to play with the latest miner/SDK combos under Ubuntu.