is an oral contraceptive pill which is to be taken regularly for at least one month before it will give protection against pregnancy
. It will not give protection against pregnancy if used only after unprotected sexual intercourse.
Marvelon will not help to avoid pregnancy in your case.
You need a prescription for an emergency contraceptive pill
which needs to be taken within 72 hours of unprotected sexual intercourse. Do consult your doctor for the same.