How to download bought apps without old credit card?

I changed my residence and cancel my old credit card. Now I did a clean install of OS X and want to download purchased apps and free apps (Aperture, Keynote and iPhoto) but the App Store asks me for my credit card info and since I don't have it anymore I can't do it.

What can I do? How to change my credit card info to that where I'm living now? Will that respect my purchased apps?