Product markup 2.9% plus $.30 transaction fee

I have marked up the prices of all my products by an additional 2.9% and have configured Zencart to discount 2.9% from the total order cost, when the customer selects to pay by check or money order. I would like to include a $.030 transaction fee for each order, and also deduct $.30 from an order when the customer selects to pay by check or money order.

Can any of you PHP / Zen Cart Wizards tell me how to make a modification to add a $.30 transaction fee to each transaction (order)

AND... Deduct the $.30 transaction fee, along with the already active 2.9% Discount for Payment by Check or Money Order.

I am using Zen Cart 1.39h

my Zen Cart address is http://emvcoop.enchantedlands.org

I have search all over and have not found an answer to my question.

Thank You... Kirk Shoemaker