Not an expert at all, but the first step is to determine how many phases the driver has. The pdf indicates how to tell if it really is a 2 phase bipolar version.
Here is a link to Danaher, which owns several stepper motor companies. You just plug in the specs of your driver, and then it will help you select the motor model you want.
I learned from their rep that they build to order - about 1 week to deliver in most cases. They have pretty high end motors and some special magnetics technology to enhance performance. The prices I got from their rep for size 34 motors were pretty competitive, and made in N Amer. There was a $ 250 min order.
http://www.danahermotion.com/website/usa/eng/index.php
PM me if you need a link to their rep.
They have some models with very high end bearing sets that can eliminate one bearing set in some arrangements.
Good Luck.