Are you sure that it is 520px wide? I'd say its roughly 800px in width - the page you've given as a sample.
You can create regular 3 column layout - give a fixed width of around 260px per column. Use floats to align your layout.
For rounded corner boxes, you can generate your CSS3 code snippets easily here: http://www.css3generator.com/
Hi Sudarshan thanks for that, your right about the width I don’t know where I got 520px from