Despite what the seller says, the dual clutch transmission (called by Audi "S-tronic") was not available on that model. The quattro used the conventional torque converter type auto, and FWD models used the CVT-type (called "Multitronic" by Audi).

The sellers car is therefore a Multitronic. This gearbox was a bit of a nightmare for Audi - and many of its unfortunate owners. One year after the car that you are looking at was built (i.e. 2007) Audi redesigned the clutch pack to change it from 6 plates to 7. The jury is still out on whether this has fixed the problem.

Try googling "multitronic gearbox problems", and then see if you are still interested in this car.