My content shifts to left of screen when I add new widgets

Please help. My content shifts to left of screen when I add new widgets in single post and archive and category pages of my site, in this template.

The following image shows the problem i am talking about. This happens whenever I add any widget except the WP25 (ad) widget. Even a simple facebook like box causes the contents to shift to the left!

https://lh6.googleusercontent.com/-iK1w7Ac2_1o/TmiZi7XSaRI/AAAAAAAAAgM/WWyvys5Y-vA/Error%2BContent%2BShifts%2Bto%2Bleft.png

I am new to wordpress (was on blogger earlier).