Google Adsense Placement.

Hello,
First: I’m trying to place Google Adsense at the top of my home page as well as all of my other pages. I’m currently using the Mystique theme. Do I need to edit on of the PHP pages or is there a plugin I can add. Also I’m guessing it is one of the PHP pages, so if so what one.

Second: On this theme I would like to use the Secondary Sidebar but It is telling me that the only way I can us it is if I us one of the widgets. But I would rather place the Adsense on the second sidebar and not at the top of the page like I stated in my first section. I’m guessing that I would need to as well edit a php page if that is the case, which one.

-Brandon