Sidebar ALIGNMENT improper

I am using this WONDERFUL theme on http://www.arnav.bookrum.com However, if you scroll right to the very bottom, you will notice that the RIGHT SIDEBAR is showing BELOW THE CENTER COLUMN instead of the right of it. I have very less coding knowledge.. can someone please tell me how to shift the position or decrease the width of the right sidebar so it shows to the right.. Please guys.. this should be easy for many here.. thanks….