Hello mate and welcome, I don't think it is that difficult a job, you can get double Din units anywhere and most audi dealers will have specific adaptors for each vehicle.
http://www.ebay.co.uk/itm/181227202821?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
The company selling the...