If your vehicle remote no longer works you can take it to your local locksmith to have the battery tested. That would be the least expensive solution if that is the problem. If that does not solve your problem you can inquire with your local locksmith regarding a replacement.
Most auto dealerships try to say that they are the "only ones" that can replace factory remotes and keys which in most cases is no longer true. Locksmiths have the equipment and access to programming both remotes and transponder keys.