Adding a second Sidebar

Hey!
I have the site http://www.estonianfreepress.com and I really need to add a second sidebar there to give space to some columnists.

A fantastic thing would be to enlarge the header, the bar right next to it and place the new sidebar “naturally” next to the one already there but I have no clue on how to do it.

Honestly, I could even contribute to the efforts if someone will have time to spend on helping me!