USPS Priority Mail International

Hi, I'm running ZC V 1.3.9f
I have a customer asking if I can ship to Canada using Priority Mail. The only option I have for shipping is USPS Priority Mail.
Using the USPS module, I have Global Express and Priority Mail International both selected in the options boxes.

If a customer from anywhere makes an order, then will the USPS module automatically return the rate for shipping Priority mail in the order box before checkout? Is there anything else I have to setup to get this module to work for priority mail international shipping?

Thank you.

More On USPS Priority mail Option:
I just found out that in the "change address" field to CHANGE SHIPPING ADDRESS, there is no "Country" option under "state/Province" how do I add Canada to the options for this field? Thanks.