Single target Sorc melee stamina build help

So I made a dual-wield medium armor sorc stamina build that has awesome aoe damage and survivability. However, when doing dungeons I tend to get a drop in dps when fighting a single target boss. I am currently using a 2-handed weapon as my second weapon and the only real good skill to use against the boss in rapid succession in wrecking blow.

Any help is greatly appreciated.