My husband Mark and I just purchased our first home. It use to be a duplex and was converted into a single family home. However, we have two different heating systems: 1) Forced hot air on 1st floor 2) Radiator Heat on 2nd floor We live in New Jersey - and my husband "can't take the heat!" in the summer. We would like to install central air conditioning - however we need to "cut" vent hole in the ceiling of the 2nd floor. All the walls and ceilings are plaster (and have all been repaired by the previous owner). I would like to attempt to cut the holes ourselves. ANY SUGGESTIONS? Also, we have a small half bedroom that I would like to convert into a walk-in-closet. However, I need to close up a doorway. We took off the door and molding, and "studed out" the hole. But we don't know what to do next. Is there a plaster kit at Home Depot? The repair is in the closet and will be covered with clothes. I think this would be a "great learning curve" to learn to apply plaster. THANKS FOR ANY SUGGESTIONS IN ADVANCE.