Here is how to make sure your OS X is updated.
Select Update Software... from the Apple menu at the top left hand corner of the screen. Before you do this make sure that you are connected to the Internet.
Apple will search for updates to your installed software and then display a list of the updates available. Select the updates you would like to install and click Install.
A popup will appear asking you to enter an Administrative Name and Password. Enter this and click ok.
If a license agreement appears you must accept this to continue.
Apple will automatically begin to download the requested updates and install them.
You may be requested to restart the computer. Click Restart to restart.