bacillus is right here. the cards and routers (or rather the chipsets in them) are usually universally capable of hitting those higher channels. locks are usually in drivers or firmware.

see if you can find drivers for a specific country (perhaps at an internation site of the card maker) or a generic driver for the card's chipset.

realtek chipsets (if I recall correctly) will let you set the region if you use the generic drivers from the realtek website.

dell true mobile cards (broadcom chipset) will let you as well -- you just need to download the appropriate driver package.

I could be wrong here but depending on the make of wireless card you use, it may all lie in the driver you use.

I recall on my old netgear 511T, you had to choose what region your were in during the driver install.