Well - that worked! I have never embedded anything before and I wasn't sure to delete what came up when I clicked the 'edit html' box, but I decided to leave it there and see what happened. I just pasted my code in and clicked on post, and there it was!
I am not sure if there are other sites that have better characters or voices on them, but voki.com would only allow me to type a small amount of text into the box, unlike Scott's avatars on Moodle. Does anyone know how to solve this?
Next time...the 'real' avatar!