The only system with color display evr fitted in the A3 is the RNS-E DVD system
AUDI Navigation Plus RNS-E 2011
Behind the display you will find 2 SD card slots which are intended for audio and MP3 playback.
Certainly not for copying maps from CD to SD card
If you have a CD system with the facility you describe, it can only be a reftrofit RNS310 which only came on the market in 2009