Need to make layout psd into a working webpage column issue

I don't have code to show yet but it's really quite simple. I have 3 colums, the first will run the height of the page, the other two will fill the rest of the page in width then end after a certain point at the same height for both, then I want to start a new section below the 2nd and 3rd column, with 4 smaller info boxes. I assume I can make a box model and place them some how in equal distance apart. The problem I'm running into how to place anything under column two and three without it also trying to go under 1st column, how do I clear the last two and start new section below them? Ideas?

XXXX XXXXXXX XXXX
XXXX XXXXXXX XXXX
XXXX xx xx xx xx
XXXX xx xx xx xx
XXXX