Grab Logged In User's Email Address

I have this asp page (see code below). It grabs the values from the previous page and populates the email which gets sent to the recipient from the person bidding on his product. I need to grab the bidder's email address (he is logged in when sending this email) from the database.

I can't seem to figure out the code for grabbing a logged in visitor's information from the database to display in the "From" field. Can anyone help? I need the code that grabs his email address, and the code that goes in the "mailer.from" variable to populate that field. Here's the code: