You want to use a common template hook or template. For example: If you put your code at the bottom of the "navbar template" then it would show on every page that used the navbar. There is probably a template hook that you can use that will work better. Sorry, I am just not familiar with the standard vbulletin templates.
When I get home I will take a quick look for you. Maybe one of the smart lads around here will point you to the right template hook.