Hi retro_killer_clothing,
No, I regret to inform you that it is not possible to change the Auctiva winning bidder emails, or any of the other automated emails our service can be used to send, to reflect your email address as the "sent from" address rather than the Auctiva email address that you are referring to.
If you have any additional questions or concerns, please feel free to contact our customer support team using the web form on the following page:
http://www.auctiva.com/help/requesthelp.aspx-Mike