I used to work on aluminium parts in the aerospace industry. Aluminium is a very soft metal, hence the bending of the case and the absorption of energy from your drop.
My advice would be this:
1. In order to do an effective repair, you would need some skills in basic metal working. You need to split your repair work in two basic parts:
A) Priority Nr.1 should be a mechanical and functional fix:
I would completely disassemble the whole notebook and separate the metal chassis from the electrical parts. After that you can use metal blocks to carefully bend parts back in its original position to allow normal shut/closing functionality. Check out youtube if you have not done this in the past. With heavy bend angles there is a chance of breaking of thin metal on critical areas! Be careful!
B) Priority Nr.2 is cosmetics:
Depending on your craftsmanship you would have various chances for getting the damage fixed up to 9.5 points out of 10 depending of budget.
1. Finishing of the surface in the visible area:
- Grinding with paper and water/oil (400 & 600) for rough areas. (start inside first to inspect outcome!)
- Polishing paper and metal finish products. (metal polishing or metal rubber)
- Sometimes a Drehmel Tool for rough metal grinding and polishing can help
- Look for information at local manufacturing and machine shop companies and ask if they do metal bruising and/or sand blasting for metal finish.
- Consider aluminium oxide coating finish.
- Just ask people like below to get an idea whats possible.
http://www.metalfinishingco.com/finish.html
http://www.aclassmetal.com.au/metal-finishing-services-general.php
I am sure they can help or have other ideas. Make photos, send them a picture and ask for a quotation. Asking does not cost you a nickel. Maybe they have some ideas.
One problem you will encounter:
If the damage is not significant, you may just bend the parts back and be done with it. This way you have to live with the scars on the outside.
If your damage is "big time" and a simple bending will not be satisfactory to you, you need to grind. This most likely means you have to do the whole part, not just the area of damage. Otherwise you will have only a partial area grinder and the whole thing will look odd. This would mean more cost and maybe
professional help. Consider also an airbrush. Maybe you consult with a professional artist to do a fine art airbrush on the back of you machine to mask the damaged area. This way you even get a unique item.
Good luck!