Welcome to the forum Seano, you'll find the members on here are a friendly and helpful bunch :)
The short answer is yes, the Sat nav will fit straight in as long as your radio is double din. However I'm unsure about the antenna. My advice would be take everything for the radio and satnav off the car being broken. I.e: radio, antenna, wiring/connectors and you should need the radio code for the new one. This will be in the cars hand book.
With regard to the Audi Bose system this will work with any Audi radio. The parts you'll need off the Audi being broken are:
Speakers including the one in the dash
Subwoofer
Multi channel amp (hidden in the boot)
Processor unit.
Mic which is in the interior light.
Plus wiring which runs from the head unit to the amp/sub.
If in doubt take everything radio related!
Hope I've helped :)
Cheers
Steve