Hi Antonio,

You should:

• Load Google Webfont homepage:http://www.google.com/webfonts

• Download the font you want to use clicking "add to collection" and "Download my collection", then install the font on your system.
• Run WebsiteX5.
• Add Google's font CSS "import" directive in the "Custom code for the head section" field at step 1 (expert tab).
  
• Use Google's font in a text-object
• Export and update your site online.