Fix a dent in aluminum? Did you ever try to fix a dented Coke can? All I can say is get a Invisibleshield/Wrapsol and a sleeve for your next MBP.
I know how annoying a scratch or dent can be. What I would do is sell it right away and buy a new one. You'll get a better price for a new MBP with a dent in it, than an old dented one. That's just me though, and I resell my MBP every year to get the latest

My 2009 13" (2.53) had a small dent in it actually, sold it for the price of a new 2010 (2.4) MBP