RE: enlarging plans?
As others explain, there is a difference regarding the process of enlargement between paper drawings and electronic (AutoCAD) drawings.
Paper drawings need to be scanned and converted into a less flexible electronic form (depending on the type of scanner), which is then scaled up (1.5 times in your case).
Note that the width of lines will increase 1.5 times, and that any dimensional text will not apply.
Any local Office Depot or Kinko's store can help you with your project.