App development for iOS and Android - open to bidding

The app we want to bring to market in Australia should be quite simple in nature. It doesn't require a great deal of complexity. The first app we want to bring to market on iOS and Android will utilise a Google Maps map location, with the ability for users to anonymously pinpoint places on the map with a headline and comments for other users to see. The purpose of this app will be for Police and Boozebus locations. So if one user within the city of Melbourne can see that police have setup a boozebus or a police road block, an accident has occurred, or an officer is patrolling a certain area, they can pinpoint this onto a location on the map, which other users will then see. The app will also notify other users in a 2km, 5km, 10km radius (maybe more, maybe less) via push notifications, they can receive notifications based on their location and this can be altered in the settings within the app. Additionally, we'd like to monetize this by placing an ad on the top and the bottom of the screen. If you have any suggestions as to how to better use non-intrusive ad placement, or a more suitable/lucrative method of monetization, we are open to hearing them. :)