Android App Modification

We have a current android app that interacts with our reposession database where our field agents can update the records via there android phone. Our database is integrated with google and the android user has to use thier login to access our database through thier phone We are wanting to add a couple of features to the app. when a agent is logged into the system the new features need to do the following: 1)Recieve a alert on the phone when the agent is within 1 mile of a address where a vehicle is up for reposession 2)Recieve driving directions on thier phone to that address or via gps 3)Recieve a alert when the agent is within 150 feet of a vehicles address . we have the file for the app that we can email