主要内容窗口小部件与右侧边栏重叠

I'm creating a Blogger theme with Artisteer for the very first time. The problem is I would like to put an ad banner before the post content. I can do that through Blogger dashboard. However, it overlaps the right sidebar. What I want to do is to bring down the sidebar if the ad is on, and if not, for example a visitor is using an "AdBlocker", it will go back to its original position.I'm creating a Blogger theme with Artisteer for