Hi there and welcome.
Well, if your iPad is already paired with a PC then just connect it to that, iTunes will detect that there is a newer version of iOS available and it will guide you through the update process (including backing up your device).
Alternatively, depending on what version of iOS you are currently running (you can check by going to Settings>About) you may be able to update OTA directly from your iPad.
Either method should maintain all your current apps but, even in the worst case (volcanoes exploding, earthquakes, floods, etc) you can always go back to the App Store app, click on the purchased tab and redownload any missing apps.
The Archangel