laudable sentiment, but am sorry to say it is not practical.  Remote villages in Nepal don't have roads for an ambulance.  Even if that was not the case, sending a vehicle to Nepal would be insanely expensive...... unless, it is purchased in India and imported into Nepal tax free.  Furthermore, assuming you are able to bring the ambulance to Nepal, you will want to make sure that there is adequate governance controls in place to not allow any misuse or corruption.