Create additional fee module for payment options at checkout page. (magento

Hello, At the moment we are using two payment method on our website, bank transfer and paypal. So basically we have two payment options on the checkout page. So what i would require is to add additional fee if the customer choose to pay using the bank transfer option. So if the customer choose the bank tranfer then the total amount before the payment is made will be added up with the additional fee. Im looking for anyone who is interested and good in magento to do this module and i would require this to be done fast. Regards,