I've just brought an A4 it's got the Audi navigation plus unit in it. but no sd card or cd for the nav? where can i get or make one up to put in? Also when i put a micro sd into a sd adapter and then put it in, it just says loading ages and doesn't load it. tried a few different ones and even a brand new adapter it's literally just the radio that works. Because i listen to CD's alot i'd prefer the SD card for the nav if thats possible?