how do I save my downloads to i tunes when I update to the 64 bit version?

We bought 2 ipad air tablets for Christmas and I have a computer running windows 7. When I plug my tablet into my computer it wants me to delete my itunes and install the 64 bit version. I have downloaded some games, a movie and a few other apps that I paid for, how do I save them so that I don't lose everything when I do the update?