Classified Ads App

Seeking a classifieds ads application that will run within a local area network so will pick up user details from their windows login (active directory) rather than website registration/login. simply need ability for staff to post ads (title,description,price,location(we have different offices), image and how long ad is to appear. maybe an optional url field also. these ads can be for sale or wanted. staff will be able to view ads by searching or by category and be able to contact tthe person who posted the ad via email. staff can manage their own ads, amend, switch off, delete etc admin area required for managing ads, categories, option to require approval activation checkbox, option for admins to be notified of new ads,