Unfortunately Nashbar doesn't provide much detail about geometry. However, based on what is posted on Nashbar's website, you should probably be on a 58 or maybe even a 61. I am barely taller than you and I would have went with the 61 c-t. That sounds huge, but the tt length of the 61 is similar to many 58s and even some 56s.

However, it its comfortable, just ride it. Its a $200 bike after all. Next time, you might consider a size or two larger.