In order to get the facebook widget, I created a developer account with facebook and inserted an iframe. I then specified the dimensions of the iframe, such that it is 160px in width and 487px in height. I didn't use a plugin. The code can be seen with firebug, but I'll also insert it below:
<iframe scrolling="no" frameborder="0" allowtransparency="true" style="border:none; overflow:hidden; width:160px; height:487px;" src="http://www.facebook.com/plugins/likebox.php?href=http%3A%2F%2Fwww.facebook.com%2Fgreenpassivesolar&width=160&colorscheme=light&connections=10&stream=false&header=true&height=487">
Because the mag theme is configured to have two sidebars of 165px (? - I think) each in width, the 160px declaration seems to work. I might have added code in the css to center and add some padding to content in the widget.
Hope this helps you.