They are commonly called, "Angel eyes". Someone was selling the entire kit for like $40 on eBay. I think the hard part is getting the head light housing open. Here is the instruction:
CelicaHobby.com is an independent Toyota Celica enthusiast website. CelicaHobby.com is not sponsored by or affiliated with Toyota Motor Sales, USA, Inc. in any way. The Toyota and Celica names and logos are trademarks owned by Toyota Motor Sales, USA, Inc.