Yes, if you recreate your site, your database tables will need to also be replaced and will cause you to lose any content that was added after you created the site the first time.
This is unfortunately a limitation that we are hoping to resolve in a future version of Site Sculptor. In a future version, we hope to provide reentrance into the Site Sculptor extension for you to make any changes/additions to the site after it has already gone live. In doing this, we need to ensure that any changes made won't effect the content that has been added in the CMS. So, it is quite a complex task and we want to make sure it doesn't add too much complexity/problems to this product.
PowerCMS 2 is currently the best method for creating new pages in your site, but yes, it is a single license per site. There is a discussion on another thread regarding using PowerCMS on your local server for all your sites you need to maintain, but only moving the Site Sculptor site and CMS live. This can be a little tricky to work though, but since it means only having PowerCMS 2 installed on your local server, it does not break the single site restriction.
See this post for more information:
showthread.php?t=13411