please explain a little more:
What exactly are your versions now?
You upgraded from Mac OS X (10.5.8) to which version?
And you upgraded to which version of GarageBand?
And what is the" everything it tells me to do"?
it replies that my version is too old or something
The version of what? Is your GarageBand version to old, or your GarageBand project version?
What sometimes can happen after upgrading the operating system and then reinstalling the iLife applications, is that you install from old installation media. Then, when you try to open your projects, you get a warning, that the projects have been created with newer versions of the software. In this case, upgrade GarageBand using Software Update, before you try to open one of your projects.