How to pull forward recepticle boxes to far back...?

Question:I am rehabing a house and the recepticle boxes were attached to studs. When the drywall was put on, the recepticle boxes sat too far back, and the front recepticle covers will not screw on properly. How do I fix this without ripping out the drywall? Also, some of the recepticle boxes were plastic, so I cant remove the recpeticle box cover...?

Thanks!!

Answers:
go to home depot or Lowe's they make extensions just for that purpose