How can I resize these areas in the Portal theme?

I want to resize the page (white area) and black footer area directly below it, but I can’t seem to figure out how to do so (even after using firebug)

Here’s how it currently looks:
https://i58.tinypic.com/6s8j0p.png

Here’s how i like it to look:
https://i61.tinypic.com/15x7iud.png
https://i57.tinypic.com/wwjhqg.png

Thanks!