The HTML file is located at:
On line 40 (and line 62), it requests the billing information. You will have to change this callout to customers name or the like:
<td valign="top" style="padding:7px 9px 9px 9px; border:1px solid #bebcb7; border-top:0; background:#f8f7f5;">
If you need help changing the callout, let me know.