I would recommend looking into purchasing
fotoquote, especially if you think this will be more than a one time occurrence. It is very reasonably priced and you will more than pay for it with this sale. Plus it will help you not underprice yourself and will give you a reference and reference point. It's surprising how much companies can be willing to pay; for example, I recently sold a very non-unique, anyone-could-have-gotten-it photo (also on photographers direct) for use in a textbook, less than 1/4 page: $375. If you are unsure of fotoquote for now and would like me to provide a basis starting point PM with the details. Good luck!!!
Jason