Scrolling Announcment and SCRIPTS [Specific request]

I have a very specific want. I would like to promote the use of the chatbox on my forum. To this end, I have added an announcement to my forum page, but I would like to add script to the scrolling announcment box so that it says how many people are logged into the chat (like the "who's online" section does).

i.e. if you have the chatbox installed on your forum, when you're logged in it will say something like:

There are currently 4 user(s) logged into the ChatBox:
[Join the Chat]

And I would like to add that code to the scrolling announcement. Problem is, I only have the "Rendered" HTML because I have no access to the source. I can get the "Join the chat" part but I want the "x user(s) logged in" part to show up at the top. I'm sure someone here knows what I'm looking for... thanks in advanced!