Mobile development

I need an iPhone/iPad app. I already have a design for it, I just need it to be built. I need an easy mobile app that allows users to be informed of upcoming job assignments for shift work that informs them of rate of pay, hours and other details (dress code, license requirements, location of assignment, point of contact etc.) Simple notifications, scheduling opt-in and easy cancel and re-schedule functionality. Each user should be able to easily invite new members to download the app in order to view available jobs. As cancellations occur, the job opening re-notifies members of the available opening. The admin functions for the Admin shold allow viewing of stats for each user individually and the group overall. This would compile completed shifts and project the payment owed to each worker who worked the project/assigment. Location services and clock in/clock out for the worker to match the assignment location adds a level of audit through the worker's mobile number. A photo upon arrival/clock in should also be collected for the same purpose. This app should be for both Android and iPhone. A good programmer should be able to do this for $300 or less.