More than likely, you will need to get a string made by a custom dealer. That's a fairly old bow so it may be pretty difficult to find one at a dealer. I would suggest getting in touch with Lancaster Archery. They have several custom string makers both on staff and under contract. They have pretty reasonable prices as well. http://www.lancasterarchery.com/

Just tell them exactly what you have and which draw length module you have installed and then you can discuss which material and twist and such with them.