Editing the Sidebar

WordPress version: 3.5.1
Superslider plugin: 1.6
Plugin version: 1.6
I did this: I edited the default_horizontal.css
I expected the plugin to do this: The sidebar should stay where it is and shouldn’t get over the content.
Instead it did this: Check the images.

Explaining
I didn’t want the users to open / hide that slidebar because it was looking really good with my theme. And there was big empty spaces on the left and on the right. So I thought that I could use this as a column. Edited the default_horizontal.css a little bit and ended up to this: Image
But I have a problem. ^ That image was taken in a 1600×900 monitor. When on a monitor with a smaller width or when the browser windows is smaller, the sidebar comes over the page. Image
How can i fix this problem? I want that sidebar to be a part of the webpage.
I haven’t bought that domain yet, you can preview the page here.