1. Just say what you want and need to say to the priest, openly and honestly. Let him advise you, and take his advice.
2. If a couple married outside the Church and neither was Orthodox at the time, they are still considered married if one or both later convert. Some priests might suggest a church wedding or blessing after conversion, but this is not universal.
If an Orthodox person marries outside the Church (whether his/her spouse is Orthodox or not), that marriage is not recognized by the Church. Many priests might also consider that the Orthodox spouse(s) have separated themselves from the Church in doing so.
Orthodox marriages between an Orthodox and non-Orthodox may be permitted in certain situations, usually if the non-Orthodox spouse is Roman Catholic, traditional Anglican, and, in some jurisdictions, traditional Lutheran. But, again, such marriages are approved on a case-by-case basis. Non-Christians are forbidden to be married in an Orthodox service, unless they convert first.