International Calling from my Brenau Vonage account

International calling is available.  To place an international call from your U.S. phone number. Dial 011 + Country Code + Area Code + Phone Number.

International calls are billed on a per minute basis.  Go here to find out the rate your the country you are calling:  https://www.vonage.com/business/international-rates/

You can read more about this feature here.