Emergency contraception?

My girlfriend and I had sex twice one night ? the second time, we had to change condoms because she was dry and the lubricant had run out. Before I put the second condom on, she asked me to "put it in" without it on for a few seconds; which I did ? not entirely all the way though. I instantly realized the mistake and withdrew. Naturally, as I expect, there is a small chance this could have gotten her pregnant. However, this was four days after her period ended, and the condoms we were using had nonoxynol-9 on the inside and outside. I had not ejaculated yet, as a matter of fact, I never did... and I had wiped the tip of my penis prior to doing this to avoid any pre-cum. My question is this: I'm hoping I'm right in assuming the chance of pregnancy is minimal ? however, we are considering emergency contraception. What could you suggest?