I'm about to head to work.
If I get a chance today...I'll PM you with info/Links etc regarding the matter.
You will need a special set of 'keys' from your dealership (check the owners manual/folder - you never know, the previous owner/s may have already purchased them). Impossible to remove the RNS with out the keys....or destroying your dash/RNS. The GPS antenna is connected at the rear of the unit, and the 'puck' has a magnetic base and will sit as high as possible under the dash.
Fair to say that your present antenna is probably the original and although it will be plugged into the rear of the unit, the 'puck' itself may well be hidden in the roof etc. Not sure of the R50 antenna location ex-factory. Maybe Bails or someone else who owns one, will chime in. However, an aftermarket antenna will do the job very well. Overall...it's a 5 minute job to disconnect the old and install the new.
They look like this:
and are inserted like this:
Cost about $20 - $30 for the set of 4 from any good Audi/VW Dealership near you.