BTW, I'm surprised they let you post at all, unless you have a 501c3 designation, stating that you are a tax-emempt charity. When I set up an account for our local animal shelter on Petfinder.com, I had to provide 501c3 information to them.
Petfinder has a classifieds section. People who find a stray can post it, or if you are specifically looking for something you can post as well. That's how I found Tibby, I wrote an ad saying I was looking to adopt a siamese or siamese kitten and I got an email from a shelter saying that they had one.