Add Subscriber keyword to email

Hi there,
We have a market auction setup for our members to create their own Buy Now auctions. Does anyone know how to add the Seller/Subscriber/Owner name/email to the email notifications? The email settings only indicate the host [site_name] email. Is there a keyword for the Subscriber?

I have edited the mail message in the wp_admin.php but would like the subject to include the seller and not just the primary host.
Thank you!