help fix my car for medical reasons

I am a 63 year old disabled pastor with no paid employment taking care of my spouse of 71 who has dementia and possible alzheimers.  We have no outside assistance of any kind so it all falls upon me.  My car is essential for both our support and our transportation, since the bus is too painful on my damaged back and arm, and also unreliable where we live.  I need to replace my transmission, and there is no extra money to be had living on disability insurance alone.  I desperately need help to continue the ministry I do, to get to church and also doctors appointments, and I can't replace the car I have.  I am not asking for much, just help.