Hi there davidlx!
I have some information for you that should be able to help you get iTunes updated on your PC. The first article I would like you to look at is about using Software Update for Windows to update iTunes, and it can be found here:
Another way to update your iTunes software would be to uninstall iTunes from your PC, then download the latest version of the software. iTunes requires that the programs involved with iTunes be uninstalled in a specific order, more information on which can be found here:
And you can find the latest version of iTunes available for download here:
Thanks for using the Apple Support Communities. Have a good one!