The first question, that you haven't yet answered, is "How old is your AutoCAD?".
Express Tools didn't always come with it. I remember having to zoom in on a line of text, construct polylines over it on a different layer, and offset the polylines to make closed shapes that I could fill in order to make a nice label. What a pain in the ass.
If your AutoCAD is new enough, install the Express Tools, explode the text, and then you can screw around with the lines and arcs comprising the text to your heart's content.
Mike Halloran
Pembroke Pines, FL, USA