App integration with Gps external navigation apps

We have an existing app for iPhone to find restaurants and pubs in seaside towns with Gps localization. The app is based on a database and the request to the database is managed through a web service. Now we want to give users the possibility to integrate the search with two important Gps navigation apps running on iPhone. From the details page of the restaurants the user will launch the external Gps app to find the route. Budget: 400 $. Please bid only if you have experience in this kind of integration for iPhone.