If this is a new site like you mention I've found it very common for the search ranking to bounce around. As both the content and any inbound links stabilize it will probably settle into it's normal ranking location. I've read and experienced that any changes made to a site don't really show up with the search engines for 1-3 months. If your site is only a couple weeks old it will remain pretty volatile for at minimum another few weeks in search results. Best of luck to you!
