SiteAssist generates a Home page and a template. Changes to the template are reflected in all of the pages except the home page. You can modify the Home page all you want without affecting any of the other pages.
As I remember, you can just select the "Best in Class Marketing Consulting Services" text in design mode and type in what you want. Then save the page.
The background images are in the siteassist_images folder.
The home page image is header_background.jpg
The other pages use subheader_background.jpg