moving the store index file is not supported.
if you want the store to be at the site root, you should install the store at the site root, other wise, you will need to have your own site index file that contains a link to the store files.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.