Now I'm no expert on this forum but here in the UK we have companies that can do "Paint Free Dent Removal". The finished result is dependent on the actual paint age and condition. I haven't used this process on my Matrix (it's only a couple of months old) but my Wife seriously banged the nearside front wing of her Citreon Saxo when it was just 3 months old and I swear, when the technician had done the work I could not see a mark! I would definitely use them again!! I am an Engineer by profession.
Do you have such companies in your country? If so and your car is not too old or paint is in good order, it may be worth investigating.
I paid £50 to have the whole wing rectified. The charge was £50 per panel regardless of amount of dents!
Regards,
Jack
PS this is a link to one such company (not the one I used)
http://www.clean-image.co.uk/dents.htm