To dimension your hole location, you need to expand the hole feature, then edit the top sketch. THis sketch contains points, which locate each hole. Just dimension these points as you would in any other sketch. You can also add points to add holes if you wish.
When you made the hole feature, if you first selected the face and then clicked on the hole feature icon, a 2D sketch would have been created. If you first invoded the hole wizard, and then chose a face, a 3d sketch would have been created to locate the holes.