iphone app for store locator for product search

I am looking for an iphone (& preferably cross platform) app developer who can develop a simple locator app. The app needs to be able to pinpoint the users location and then they will enter a product in the search bar and the app will tell them where the closest store with that product is to their current location. It also needs the option to send the nearest store location to the person when their phone's battery (may only be possible with iphone) hits 20%. Apart from that it will just have the different kiosk locations and a Google map connected to each kiosk location so they can be found easily. Needs to be able to be updated regularly by me with products and new locations. This needs to be done on a limited budget so please include ways to keep costs down for the app and also to make it possible to be edited (like a CMS - if possible). Thanks