Car Sharing application for ios and Android Latin America - repost

We are looking to create a Car sharing application for users in main cities in Latin America which will allow drivers and passengers to share their route to work or to the university in real time. The idea would be for a "Driver" that has a car, to offer a determined amount of available seats and define a route to find people belonging to their same company or university and share the car. At the same time, a person that doesn't have a car, can look for somone that do has a car and goes to his company or university and is willing to pick him up. Each person must have a profile integrated with facebook and twitter which will allow them to share the app and find friends who use it as well. An idea would be to have GPS in the app but it's not mandatory and if it can be used with the integrated maps application of the smartphone is ok. We want to develop the app for iOS, Android and possibly blackberry users, it must be completely in spanish and easy to use. We have no idea on what it should look like or hat should be the best distribution scheme for it but we know we want an app that's pretty easy to use and user friendly at all times. The business won't be awarded to the best price on quote, but to the company that better shows examples and proposals on how they will develop the app and show experience in similar projects. The project should include 1. Designing the app and go live of the app on apple and Android markets 2. Designing of logo 3. Design of website Attached you'll find a file with the example proposals we want to receive, since this is an app, we don't only need text, we want your offers to be as graphic as possible.