I later discovered that you need just to get a non impediment paper from the Local Register in your country and send it together with other relevant certificates(birth,residence,copy of the passport, etc..) to the Embassy here in Rome.Then receive a "Nulla Osta" here, book the City Hall(cost about 350 euro) where the Ceremony(Civil) will be held and just be in Rome 1 day earlier to sign the Local Marriage Register.
Of course it helps to have someone here but overall it will not cost a fortune.

