If its the same as a B6 & B7 and most other Audi's for that matter , remove the wheel on the offending side , remove the inner wheel arch cover, you don't have to take it all off just enough to gain access to the front of the car and there should be 3 nuts attached to captive bolts, these are what hold the bumper to the wing, loosen them off adjust the fitment and retighten them