[Theme: Twenty Twelve] set responsive menu button position

Hi,

First of all, I’m using a child theme.

I’m having a hard time dealing with the responsive menu button, that appears below 600px window width.

As far as I can make out of this, there’s more issues with my layout. Please see the link, shrink it below 600px. My content text gets mixed in between header and site title and the menu button floats on the top. What am I doing wrong?

Any help is appreciated.