Talk with the pastor of any of several protestant churches in your area where the full gospel is preached and they believe in baptism by immersion. If they are more interested in the salvation of souls than the increase of numbers in their church, they should be willing to baptize you. Some churches require baptism in order to become members, but since you are not seeking membership I can't imagine any church refusing you baptism. If they do refuse, then you shouldn't want to become a member of their church anyway.
If you fail to find a pastor to do this for you, then find a Christian friend to take you to the river and baptize you there. I find no requirement in the Bible that says a baptizer must be an ordained minister.
