Greetings,
your project sounds very interesting. I can start working immediately after we discuss project in more details. I can help you with Google Sites redesign but please keep in mind that limitations you mentioned can make us trouble. However, we can do some magic there by linking graphic elements to certain places(pages) on website and by that mimic standard webpage elements (eg. navigation). Furthermore, if your decision about staying with Google Sites isn't final, then I strongly suggest talking with me about complete website redesign, remake and free domain and hosting management in price similar to price quoted for Google Sites redesign.
Thanks for posting. Feel free to check my portfolio and previous references.
Write me anytime that suits you, Dragoljub.