app development

we are looking for someone to help us with a project - we need a mobile app developed - we are adventure magazine and we are developing a nation wide adventure directory - so that when you are in a region in NZ you can look on the app and it will give you the activities within your area - radius to be set - we would also like for the app to be able to list a full range nation wide activities - ie - all the rafting companies - we are also after any additional ideas a developer might have - we will have full list and addresses of all activities - we would like an apporimate cost for doing the whole project