Advertising publishing and advertising creating site

I am looking for a website to be made whereby publishers can come and display the open advertising spaces on their site and set prices as they set up their ad display model whether they are banner adds spots or text add spots. Advertisers can then come and choose the add they want to buy on these published sites(can choose cost per click, cost per 1000 impression, overlay and underlay adds). This system will also allow them to create text adds as well. So basically we need a system that can track publisher payments as well as aallow the advertiser to set a . For a better understanding of the system we are looking for you can look at [login to view URL] and Adonion.com. We would like this site to be Ajax based. We would like this site to be completed very quickly as we would prefer to have it ready to go by September.