Does Intake Of Novello Morning After Pill Avoid Pregnancy Post Unprotected Sex?

Hi. I have been on the nordette pill 3mnths now. My period ended last week. My boyfriend an I had unprotected intercourse and he came in me. I have taken the novello morning after pill about 2-3 hrs later. Would it prevent pregnancy? Shud i take another dose of the novello? Please advise. Thanks