MAC US Wi-Fi card doesn't support channel 12

At one stage in my home network admin guru self exploration ride, I wanted to use channel 12 on my router, as somewhere I read it's best to use a channel that isn't overcrowded (since then I learned it isn't all that simple as just picking a channel that no other router around me uses, but a little more than that like overlapping wifi channels, and ways to avoid them [recommended read!]). So I set my router to channel 12 and was happy to acknowledge my (temporary) success. Shortly after that, my wife started to complain that she sometimes loses connection, and cannot get it back only after a couple of tries, potentially a restart or not even (well, the first few symptoms I realized are unfortunately quite common issues with an MBA, but that's a wholly different story). It disconnected so often, that I started to work on fixing it somehow, even though I had no idea what the issue could be. Finally I found it: apparently a lot depends on the Wi-Fi card used in the device; although it has been bought in Europe, it's card was a US one, which does not support channel 12. To find out the locale of your Wi-Fi card, you just have to click the Apple logo on any OSX based computer / laptop, then choose 'About This Mac', and click 'System Report...'. In the new window that opens, click 'Wi-Fi' under the 'Network' folder. Below 'Interfaces:' you'll find your card information, among others its Locale, and (recently) a section called 'Supported Channels'.