Part-1 of this series is available in the link: http://anudinam.org/2012/03/02/purana-ratnam-vishnu-puranam-1/
Part-2 of this series is available in the link: http://anudinam.org/2012/03/04/purana-ratnam-%E2%80%93-vishnu-puranam-%E2%80%93-part-2-with-upanyasam/
Thanks to Sri Krishna Sabha of Mumbai for the video file of this upanyasam. The upanyasam of Srivatsangachar Swami in this video was organized by Sri Krishna Sabha during Sri Ramanuja Jayanthi yearly event. If the viewers of this video would like to appreciate the effort of bringing this rare collection to us, please contact Sri Krishna Sabha for your contributions.