sorry for laughing, but i had this problem a few months ago, do a search for my username and you can read all about it.
i had to get them as genuine parts from toyota, i tried lots of wreckers, but they either claimed they didnt have any, or tried to sell me a new gearbox.
do you have a sample clip? only one of mine was missing, so it wasnt a too big a problem, my mate who works at toyota says they basically have a box of assorted clips that they go through to find a match. im sure someone in here will be able to lend you a sample.