Move Footer so its part of the centre column, adajcent to teh sidebar, not beneath it

hi All,

I'm running Atahualpa 3.4.9

The question I have is i want to move the footer from where it is at the bottom of the page to being in the centre column. At the moment the website looks like

C C S
C C S
F F F

C = centre S = sidebar F = Footer

I need to change it to this:

C C S
C C S
F F S

Any help appreciated!