set property of object using a script?

Hi,

Ive got a toggle object and I would like to attach a script to this toggle object, to make it behave like a button.

I can do this with a script (if I create the toggle with the script).

However, I would like to set the property for an existing toggle (by attaching a script to the toggle)

The property I would like to set is as follows.

     private bool pressed = true;

    GUILayout.Toggle(pressed, "Toggle me!", "Button");

Sorry for such a noob question, but its got me stumped...