Hi Fredy,
Try adding the following code on main php from line 46-50 between </div> on line 46 and <?php } ?>
code:
<div id='sidebar'>
<div id="advert" href="contact" style="background-color:rosybrown; position:absolute;left: -180px; top: -550px; position: relative;width: 120px;height: 300px;"> Advertisement </div>
<div id="advert" href="contact" style="background-color:thistle; position:absolute;right: -1020px; top: -850px; position: relative;width: 120px;height: 300px;"> Advertisement </div>
This will put 2 colored banners on the left and right respectively. You can adjust the size, color and position as you want. you can also try to duplicate as in your photo.
As for adjusting the position of your sidebar, that will be found in the bootstrap mini-css.
Regards