Not only that but I think your Wp theme is also forcing some margins that are causing the post to slip below the side panel.
You can go for having what is now on the left above the post by switching to the ‘stacked’ theme – there is a download link for themes on our main download page.
Or you could edit the spTopicView template in the current theme – which you can do with our theme editor. If you open it you will clearly see a code block that behind Column 1 and another as Column 2. In those calls to define each of the columns is a percentage width… you can juggle those until you get it to look right.
As always we recommend that you create your own SP theme so that any customisation is not lost during a future update. (http://codex.simple-press.com/codex/themes/theme-basics/creating-a-theme/)