my Macbook Air says it is running the latest version but it is stuck on 10.6.8. When I check for updates it says there are no new updates. I don't want the latest one which seems to be problematic for everyone (is that true??) but I would like to go to 10.9 or the one before the latest one. How do I do this? I have tried through the store but it just says I already have the latest software.
Unless you have the very earliest (Jan 2008) model you should be able to upgrade to Yosemite. Check your Mac model, click the Apple icon at the top left of your screen, choose About This Mac, then choose More Info.
You can't upgrade to an older version (unless you have a copy of the installer for that version).
Mavericks / Yosemite are not updates to 10.6, they are new "apps".
In the App Store, search for "Yosemite", it should be the first result. mavericks is no longer offered directly but may be available by less obvious routes.
Also note that if you have an original Macbook Air it may not support the latest operating system.