You can order Comic-Con exclusives online through sites like HasbroToyShop.com
If they ever get around to putting up this year's releases. (Which still haven't been added.) And based on what I've read on collector's sites, I guarantee you that the desirable stuff will be wiped out within an hour of whatever random time the items appear.
I'm still hoping to get a second Derpy to keep MIMB, and it basically entails living in front of the computer 24/7 with HTS.com open in one tab. Bah.