Welcome to traditional archery, Big Ol.

Does that 57 say 57 @ 28" ? If it does then that means that is the draw weight of the bow at 28".

The srting length you need is 4" shorter than the length of the bow measured from limb nock to limb nock. Not the entire length of the bow. Simply measure the distance from where the string loops onto the limb to the other end at the same place. So if it is 58" nock to nock, then you need a 54" string. If there are no tip overlay's on the tips of the limbs, then you need a flemish string. If there are, then you can get a fast flight or D97 string.