Why don't your try to have the information start at the left margin.
Since each line is a different length, using the left margin will allow the information plenty of room on the card. This type of layout would also balance the logo which is in the top right corner, the information would then be in the bottom left corner.
P.O. Box 12345, Hartford, CT 06120
Office: 860-000-0000 Fax: 860-000-0000
Email:
info@mywebsite.com
www.mywebsite.com
Janet