Spudbuster

I have a 2003 LS430 and the passenger side mirror will not move up and down. Took it apart and determined that the white plastic part that the actual mirror is attached to has two plastic screws that turn the mirror up/down and side to side. The up/down screw has a broken socket in the plastic portion. I would like to find the plastic portion that has two plastic screws still intact. If someone knows a good salvage place for Lexus parts, please let me know. Appreciate the help. Thanks.