To give your site the look and feel you require there are three choices

  1. Create your own.
  2. Use one of the many free ones.
  3. Purchase a ready built Theme.

This site uses the Thematic Theme .

The choice is yours but ensure you get one that has sidebar enabled  and plugin ready.

Again remember this is about cost and the more time you have to take to get your site up  and running the less time you have to generate money.

Once you have your theme just copy (unzip it first if required) it to your /contents/themes/ directory,go to presentation on the wordpress site admin menu and click the theme .Thats it your theme should be installed check it out in your browser.