What Are The Chances Of Getting Pregnant Without Penetration?

Recently we were making love and i accidentally ejaculated near her vagina or on vagina i am not sure. and yes there was no penetration involved.
i am worried and scared about the doubts of pregnancy. She's still a virgin and the symptoms are the very next day she's spotting. And she was also expecting her periods these days. this incident happened on 6th of march and today's in almost 10th march 2014. Kindly help us what should we do. I bought two ECP tablets but yet she hasn't taken them.