Custom shipping charge

[Dan1]

I'm using PS 1.3.1 without any shipping modules such as USPS, UPS or FedX. I configured shipping weight ranges and prices and offer USPS priority shipping only. Sometimes I have customers calling and asking for faster shipping. I've started considering what is the best way to process such a phone order. I have a merchant account and accept credit cards through the Authorize.net module. I can log in to Authorize.net and use the virtual terminal to charge the customer. But I'd prefer to do it through the shop so as to have a record of the order and all the customer's information.

I use one page checkout. I figure I can just create an account and place an order through the front end with the customers details which will also be applied to the payment. However I have no way of adding shipping cost above the normal USPS priority rate. Is there a module that allows to input a shipping or a miscellaneous charge of my choosing?

Barring that the only way I can see to add shipping cost is to create a product called shipping surcharge and make a bunch of attributes with incremental price increases of say $2. I don't think this looks professional in the shop though.