I looked into a possible "DIY" way to do this and with out knowing someone at a dealer, it will be impossible.
If you search on ebay, you can find some USB drives that will update it, that is just a license file(a 4GB USB drive that only uses a few MB) BUT, you need the software that the dealer has to actually update it. If you go into the delaer and order it (As I understand the current dealer in the US costs is $169.99, a lot less than the older models, YMMV) you get a USB drive that the dealer puts in his computer that connects to the car to assign a license to your software to upgrade it.
I picked a 2013 update on ebay ($20 or so) it was just the USB drive. it requires software that the dealer has, no 3rd party or underground way (trust me, I know the underground on this stuff and it's not available there). I've never called a dealer to see if they would INSTALL my 2013 upgrade... but, I don't foresee them doing it.