Dangerell

You download the maps online, you can find them on forums for free or you can buy them directly from ebay/audi as you wish. (if you plan to buy them directly on sd cards, you don't need to buy two extra sd cards). Latest version for MMI 3GP is part number 8R0051884HQ.
You buy 2 SD cards minimum 64gb so you don't have to delete anything from the map archive as it has 37GB unpacked.
Copy the content on both sd cards, so you can update faster the maps.
Put both cards on the cards slot on slot 1 in front and slot 2 on rear, start the procedure and that's it.

Good luck.