Update A Stage Component From A External Actionscript Class File/Package

I've created a "label" which I dragged onto the stage, and I have an external class that I need to be able to update this label. But right now, it as if the class has no idea the label exists.

The external file is somewhat setup like this:

package {

import....

....

...

  public class Downloader extends EventDispatcher {

          public function Downloader() {

          ...

          }

}

}

----------------

I need a way to update the text for the label within that package. Can someone explain to me what extra steps are needed? I've searched online, but I'm just getting a ton of information which I feel isn't relevant to what I need, or it seems like they are over complicating things.