updating ipad software from ios 5.1.1
i have an ipad that is running on the ios 5.1.1 software. I connected it to itunes to try to update my software, and was told that my software is up to date, when I know it is not. There are alot of apps that I would like to use that require higher running systems. What do I do to get it updated to a more current software?
iPad, iOS 5.1.1