It's all one product. The wyBuild installer includes wyBuild, wyUpdate, and the AutomaticUpdater.
wyBuild: Builds the update patches.wyUpdate: The updater you include with your product whether you're using it as a standalone updater with silent update checking, or you're using it with the AutomaticUpdater.AutomaticUpdater: Is a component you can add to your Windows Forms or WPF app to completely automate the update process and give you events to control how updates are delivered. Read how to use it in Windows Forms and in WPF.
You will definitely be using wyBuild and wyUpdate. And depedning on how you designed your BHO you might also be able to use the AutomaticUpdater. That is, if you have a form that your can drop controls onto you can use the AutomaticUpdater.
Otherwise you can just use wyUpdate as a standalone updater (which can also silently check for new updates).
Tell me if this helps.