I would loosen the brake mounting bolt on the back of the crown of the fork, will probably be a 4 or 5 mm allen head. Then I would make SURE the front wheel is centered in the fork, then apply the front brake lever fairly tightly while tightening the brake mounting bolt. This should get you close, then use the little bolt (probably 2 1/2 or 3 mm) in the top of the caliper arm to micro-adjust the brakes to perfectly centered.

Good luck!