To download the latest version, simply visit the general App Store and search "bigoven."
Your search results show two versions of the BigOven iPad app -- the latest version and the older version. Download the first one that appears, titled "BigOven 350,000+ Recipes and Grocery List."
Once you've downloaded the latest version of the app, you can remove the old one by holding down on the previously existing BigOven app icon and tapping the "X" icon that appears.
That's it! Now you're all set to start using the new and improved iPad app. Simply launch the new app, log into your BigOven account, and all of your recipes will automatically sync.