10.8.3 Update Available But Not Installing!

For some time now I've been notified that a OS upgrade to 10.8.3 is available. Many times I've clicked on the 'Upgrade' button and told that I need to restart to complete installation. I always comply with the restart but the OS upgrade doesn't happen.

Here are the details of my MacBook Pro:

Processor 2.4 GHz Intel Core i5
Memory 4 GB 1067 MHz DDR3
Graphics NVIDIA GeForce GT 330M 256 MB
Software OS X 10.8.2 (12C60)

Solutions please.

Someone else had this problem and the 10.8.3 Combo Updater seems to have fixed the problem. Fortunately Nick has already provided a link for it http://www.mac-forums.com/forums/os-x-operating-system/297084-update-10-8-3-a.html#post1505214