For the availability of and prices of spare parts, we would suggest you walk into the nearest service centres as they will be better people to assist you. You can click on the following link to see the details of the nearest service centres and selecting your city accordingly - Service centre. In order to improve the mileage, we would suggest you drive slower. Driving fast can reduce your fuel efficiency by up to 33% if you are travelling above 60 mph. It is best to change gears appropriately and match the gear and the RPM carefully. The service schedule will be given by the service centre also.
For the current offers, we would suggest you walk into the nearest dealership as they will be better people to assist you. You can click on the following link to see the details of the nearest dealership and selecting your city accordingly - Dealers.
Exchange of a car would depend on certain factors like brand, model, physical condition, kilometers driven, no. of owners and many more. In order to check for exchange offers and value, we recommend you to get in touch with nearby dealership - Car Showrooms