Classified Website Upgrading Project

I run a classified advertising site called [login to view URL] it allows people to post ads to any of 900 city classified pages or to all of them for one low price. what i need is a admin - side posting capability that would allow me to post ads directly to the site , one any page or via a selection box, to all pages - in the same category. further , i want the option to post the ads with an option to the length of time they remain on the site before they are automatically deleted, there should be an option to let the run for 1 month, 3 months, 6 months, 1 year or indefinitely simply by checking a option box at the time of posting. clients who ads are posted in this manner should get an automatic email notifying them when the ad is posted and 5 days before it is deleted. this is all admin side, not client side access only. I will want to discuss this matter over skype with you before we move, thanks please reply with your comments Muhammad Bey