Build Monetize options for a Social Networking Site (PHPFOX) -- 2

We have partially built Social Networking Site using PhpFox. We would like to create a monetize option similar to Facebook (Boost Post) where user can select target audience (based on interest, geographical location etc) or people who like their page and run the Ad. Website Admin should be able to maintain the cost per impression that will be charged to user. We also need to integrate the payment option to Paypal Pro. User can set up payment detail and after Ad is run the system should automatically process the credit card. After the project is complete. You must provide support for 30 days for any major or minor bugs. Major bugs must be fixed immediately. If you have experience in Facebook Boost Post or how their monetize option works would be very helpful. After we select the developer we will create 4 milestones for this project. Before starting each milestone we will escrow the money for the milestone. When final milestone is completed and tested and works bug free, we will release 75% of payment. After the site is running for 30 days without any issue with the monetize option only then remaining 25% will be released. This conditions are NOT negotiable. If you do not agree, please do NOT submit your bid.