I have been working in web development for 16 years, and am experienced in working in all aspects of site development. From design, to coding (PHP, HTML5, CSS, JavaScript), to deployment.
I could happily take an existing site and give it a new design similar to ecailler-oleron.com.
My assumptions would be:
1. You already have all your own images and content you wish to use, these would be sourced from your existing site.
2. You have an existing logo, again sourced from the existing site.
3. For the "livre d'or" the scanning would have already occurred, and the site would just need to accept uploads of these pages and display them publicly.
4. You already have a hosting company hosting the site for you.
5. You already have the site translated to English.
Everything else I would be able to take care of, in terms of creating a responsive design, that is mobile-ready -- and then converting it to a template with the features you mention. Populating the site content from there should be simple.
Please excuse my writing this in English, it is how I am most comfortable writing. However I do understand French quite well, and I have a French partner who can help me with any complicated translations.