Probably the easier option would be to add a second sidebar that is on the right hand side of the content. I did notice that you’re running an old version of the theme. Before diving into a lot of edits, I would suggest updating to the current version. It handles the space of the content area a bit differently so it fills the full width of the content wrapper instead of having that space on the right.
You can download the theme from our support site here. You can unzip the foxy.zip file and rename the folder foxy-update and then zip it back up. From there you can install it just like you would a new theme.
After that if you still need to add in a new sidebar either to the right hand side or the header, let me know and I can show you how to do that.