Create a Third Column (side bar)

Hello,
I have a blog that is a template with 2 Columns:
http://www.patricksemaan.com/projektcyan

I would like to add a 3rd column to the right, that has the same background color, font type and separators as the existing column has.

Could anyone guide me on how to do this or link to a site that has a tutorial for such a thing?

Thanks!