Classified Ads :- AutoPost Script

Freelancers I need a script that can autopost ads to my classified site. It will need to be able to have many users accounts and update ads every 1-2 hours and have an admin panel too ,so that I can set up and admin accounts. i.e. it must have:- 1)A perfect script for autoposting of the classifieds that too will be updated after every 1 to 2 hrs.(Fully Automatic). 2)Here many users can register there accounts & manage them too. Will have administration panal too. 3)Here you can setup accounts & can manage them too.