Supposedly she now performs under the name of Treasure Chest.  I say "supposedly" because I can't recognize Treasure Chest as Greta, but that may simply be years and/or plastic surgery (or maybe just me).  Judge for yourself.  There are sample photos of Treasure Chest at:

http://www.photoclubs.com/vip106.shtml
http://www.photoclubs.com/vip136.shtml

There is a biography of her, including both the "Greta Carlson" and "Treasure Chest" names, at:

http://bigbustymodels.com/models/md_trsr.htm

This page includes a link to her videography.  She has continued to make both hard (at least a couple of performances in the Big Boob Bangeroo series) and soft (at least three videos for Napali, including "Treasure Chest And Her Busty Friends") videos as Treasure Chest.

The Bunny Ranch has listed her as a pornstar who has appeared there, and the Nevada Brothels page lists her, as well.

I don't know of any contacts for her, but she does have a club at Photoclubs.com, so perhaps she can be reached through her site.

Good luck following up.

--PC