My chapter has gotten stickers from a really cool lady named Cathy Neben, who owns Joe Toga, a greek shop here in Houston. You can order stuff on the internet from her.
Check for stickers that can be customized (usually a minimum order of 5 or so, so share with your sisters) or else email her and ask which of the stickers are already available even though they might not be listed as an option for Sigma Alpha Iota. She is really nice and helpful! If you want something, she will find it for you!
Joe Toga