I bought my Macbook pro in 2010 and had Snow Leopard which I upgraded when Mountain Lion was available. Now it keeps saying Mavarick is available. Is that another update? Or is that something else?

Mavericks is an upgraded System in the same way that Mountain Lion was, the difference being that it's free. You can download the installer from the Mac App Store (the system requirements are the same as for Mountain Lion so you should be OK there). I've not got it: reports suggest that it is an improvement over Mountain Lion but it has some quirks that may or may not be an issue for you. It has its own forum, so you could look there for information.