Look through here. These are all the commissioners on here that have posted..You already know about this subforum, there's a review thread here so look at that when you find commissioners you think are good quality and see how reliable they are. Then PM the ones you like and see what you can do. If it's fairly simple, 3 months should not be a rushed job, but it all depends on your cosplay..
Also, I'm not sure if you are aware, or what your cosplay even IS, so your budget may not be high enough depending..A lot of detailed and intricate cosplays are going to be extremely expensive, so keep that in mind..If this is pretty straight forward, I can see this budget being ok.