Sorry, not sure how much it would be to fix that dent...since you already suctioned it out, it probably won't be as much if you hadn't. Did you suction it out yourself or go to a shop and do it?
I honestly don't think you should have decked him first...but, I'm not gonna sit here and tell you what ya should have done since ya can't go back and change it now. In the future, I'd just peel out if the guy starts coming at you like this one did. I know you might say/think you'll look like a wuss if you do that, but who cares, are these guys you'll ever see again? It'll prolly save ya more damage to your car too