If it is under warranty, you can take the vehicle to the service centre of the respective car manufacturer, but make sure that you have all the relevant information which might have to show the proof of the warranty.
You can also search for the nearest service centre for your vehicle in the city, through the telephone directory. Explain to them about the problem that you with the vehicle. You can ask them to fix the car at your place or if required you can take the vehicle to the garage. Also ask them about the how many days you would have to keep the vehicle at the garage. Once the vehicle has been repaired, ask the mechanics of the garage to give you a test drive of your vehicle. After you feel the vehicle is working fine, you can be content with it.