The most effective way to customize the logo is to use the included Source PNG file. When opened in Adobe Fireworks, this file contains all of the Layers in the design allowing you to tweak and change any of the image elements of the template design.
In order to utilize the Fireworks Source PNG included with the Clarion template release, you will need Adobe Fireworks. The 30-day free trial of this software as well as more information is available here at the Adobe website.