Immy, you've probably been to this site a million times already over the years, but I thought it worth was a shot in the dark. This is the link to where they credit the Hotline Operator as "Tammy White".
http://www.imdb.com/title/tt0220412/
I was assuming that since the thumbnail you show of that girl is her talking on the phone, that she was the Hotline Operator character. But there's no way she could be Tammy White.