Hi
I have the same mount in my A4. I believe you can buy an adaptor for the iphone 5 which clips to the mount so the phone works through the cars stereo and also charges through the mount.
I think you need something like this http://www.ebay.co.uk/itm/Genuine-Audi-iPhone-5-Phone-Cradle-/161235625211
Or look on the Audi website.
Good luck