When do we get an upgrade??

Sorry, but no one outside of Apple knows anything about future product releases. Anything anyone here would post would be pure speculation which isn't allowed here (the Discussions are for technical support on existing products). There are a number of rumor sites which you can read, but as to whether any rumors they report have any validity, your guess will be as good as ours.

We never know.

However, here

http://mactimeline.com/

is a nice web site that keeps track of Apples releases for you.
It wont tell you when the next version is coming out, but it can give you an idea of Apples history with updates on any particular product.