Normally your conception date should be after your AF, unless what you think is an AF is actually a conception bleed. It sounds like the calculator may be wrong, or you have put your details in a bit wrong.

When I put your details into a conception calculator it gave me:

First Day of Last Menstrual Period:October 25, 2009
Probable Date of Ovulation: November 8, 2009
Possible Dates of Conception: November 4 to November 12, 2009
Due Date: August 1, 2010 (40 weeks)

Which would make you 4 weeks and 1 day pregnant.

ETA Congratulations