New Widget Area Positioning Problem
 

I need to create three widget areas (or rather, one new area with 3 cells?) positioned as in the diagram below.

http://www.neshamahyoga.com/wp-content/diagram.png

This isn't working:

Assuming I am misunderstanding alignment -- how do I achieve the desired positioning?

First off, where are you putting that code?

In my child theme's index.php file. Incorrect?

Where do you want this widget area to show up?

In the Center Column. I have three equally-sized widget areas side-by-side there already, just need to rearrange them.

1) why not use a two cell widget area and put two widgets in the second widget area?
2) instead of using a child theme, if you want the widgets at the top of the center area, put them in the 'center column top - top widget' option and use the widget logic plugin to control what page to show it on.