If you can do it, then replace the whole part that was damaged. I am sure you can buy it off ebay.
If you can't do it, sell it for parts. Or maybe if its working then use it with an external monitor.
Take it to an Apple Authorized Repair shop, perhaps. My wife dropped her Air and bent a corner the AA store we bought it from agreed to bend the corner back. It looks ugly, it cost some money. But they have the skills to take it apart. And I'm hoping they didn't put the repair into the Apple repair computer system. We have an AppleCare repair coming up, and plan to take it back to them and argue that the problem is unrelated. I think a corporate Apple store would void the warranty if they saw the damage.
Not entirely clear from your image but looks like you have broken the hinge? If this is the case, how old is your air? Hinge breakage is a known issue and it could be that the hinge was about to break anyway. Have you ended up with scratches/dents on the corner of the case/display? If so Apple will not accept this as a hinge breakage- my wife dropped her rev a air when it was two weeks old (actually she slipped and fell over while carrying it) and two years later the hinge broke. Apple took one look at it and said: 'Sorry it's been damaged, no free hinge repair." If there is no obvious external damage you might get it repaired. The only alternative to an expensive professional repair is parts from ifixit or powerbook medic....
That's what I did in the end but replacing the backshell/hinges is not for the faint hearted or first time laptop repairer.
Good luck!
Engage brain before flaming the OP! He obviously didn't know how to rotate his images. The air is on a glass table and the blue 'flowerpot' tells you which way is up, unless of course he has glued the pot to the table.
Thanks for everyone's replies. I'm going to take a trip to the Apple store and ask for them to fix the hinges gratis. If that doesn't work then I will take it to an apple repair shop. This would be a lot easier if an apple store/repair shop was close by. As for the pictures sorry for the rush job, I took them with my iPhone and hate how the browser doesn't rotate them correctly. I was so distraught I didn't fix it. Again, thanks for everyones help (except the dude that was all pissy about the pictures)!