Use the good evocations; Resilient Spheres, Walls of Forces, Contingencies, Instant Refuges, etc. allow Evocation to do so much more than pure damage. Howling Chain is a good one too. Take a cursory glance at this list; it lists a bunch of awesome evocations alongside their sources.

Also, use metamagic and Metamagic School Focus [CMage]/Practical Metamagic [RotD]/similars along with Residual Magic [CMage] to reduce the cost. This enables you to actually deal decent damage. Split Ray [CArc], Twin Spell [CArc], Energy Admixture [CArc] and Empower Spell are some of the better metamagic feats to apply.

Finish MTAO since you started it; it's a fine PrC. Then you can enter something like War Mage [Age of Mortals], Incantatrix [Player's Guide to Faerun] (tho being so many levels in, this isn't that good), Archmage or so and pick up various bonuses to your blast booms.