I don't think analytics is counting unique visitors. I think it's unique visitor within the past 24 hours. So it could be the same people visiting once per day. But don't quote me on that. You should be able to see the returning visitors stats, see how that adds up.

Time spent really depends on the type of site. 1 minute is not that sticky though in my opinion if you're creating content and trying to get people to stay on site.

Perhaps your best route would be to open a dialogue with the current users and see what they do and don't like about the site. What they would like to see more of rather than just blindly guessing and adding features.