Audi A3 ESP/ABS fault

Take the A3 to an indepentant that has vag-com. Other things can keep that light on your dash illuminated aside from the ABS pump, such as the lateral G sensor, I know as mines been acting for a while.

Get a second opinion.

Also here's a good forum for Audi owners (its offline for maintenance tonight but it shouldn't be off long)
http://www.audifans.net/modules.php?name=Forums

And as for vag being "junk", typical BMW drivers statement.

My father owns a VAG specialist garage. This is a common fault - happened on his own car last year. The parts are extremely expensive and I believe they have to be coded to the Engine Control Unit (ECU) which will require a main dealer or a VAG specialist with the correct computer.