www.ICANN.com and
www.internic.com and raise Cain on their complaint pages. If your host isn't an actual registrar, find out who they register thru and go email them this.
You can't get the site back but you can certainly make it uncomfortable for the host. We heard you can't get a thing done about that stuff but when we complained to ICANN they went after the registrar that was giving us fits and the problem was resolved.
If that domain was making $$ then you tell the host you expect to recoup those losses for at least a years worth and expect freehosting for the same time for your other sites.
BUT make sure you have the p's and q's right... check etc dated before the site expired and all of that stuff.