I purchased a vehicle in Sept. 2011. I was given a temporary tag, registration and title from dealership. The car was seized by police (long story) in November 2011 and I just got it back now (January 2012). My temp tags are now expired, and all my original paperwork is missing! I now want to sale the vehicle, how can I do this?

You will need to get a replacement title from the dept of motor vehicles. You can check the process for your specific state here:
Replacing a Lost Title at the DMV - Lost Vehicle Title at DMV.org: The Unofficial DMV Guide

Hi,I think your must contact to dealership and request temporary tag again.
Because he has all the documents are stored.
What model of car, if not a secret ?

Did the dealer not file the paper work with the DMV, I am use to that happening.

But you start with talking to your dealership and they will help you replace paper work, they will have copies, and if they filed with DMV then you will follow up with lost forms with them.