Multi-Tier Restaurant App

I need an Android app. I already have a design for it, I just need it to be built. It should consist of three apps:- 1) User App 2) Supplier App 3) Delivery App 4) Administrator App 1) User App would display the foods to choose from and place order. Foods displayed will depend on user location and the predetermined zone it lies in. Delivery charge calculator and live delivery tracker would be there. 2) Supplier App would receive notifications of orders received by it and their earnings. They can post dishes after approval also new ones can also register after approval. They are required to delivery order in given time frame say 15 min prior to which they will be charged for delaying order. Supplier have the right to cancel an order placed to them. In case of multiple suppliers if order is cancelled by one supplier, whole order will be cancelled. 3) Delivery App would have approved and registered delivery personnel who would be assigned order placed by the customer which they can accept or reject. Order request will be sent to all delivery personnel within 5km radius of supplier. In case the request is accepted by multiple personnel, only the one with least distance from the supplier is to be selected. In case order has been placed with multiple suppliers, it will be added to Google maps delivery route as multiple stops and personnel who can deliver it from multiple suppliers to user will be auto-selected. Their earnings should be visible (Extra payment for more than one supplier will be dealt by Administrator's earnings). In case cancel button is pressed before reaching supplier whole cycle of selection will repeat and if cancelled after taking goods order will be diverted to nearest personnel and canceller will act as supplier. 4) Administrator account will be supreme account. Commission earnings should be visible. Earning and orders received by suppliers and delivery personnel should be visible. It can block any supplier or personnel, delete any product, change prices and revoke price change done be suppliers. All cancellation should be visible. It can also issue fines to suppliers/personnel. Please tell me how much time it will take to do so. It will be good if you already have source code of these app and just do modifications to it.