The civil marriage is called an invalid attempt for a Catholic and you will, after it, not have a Catholic marriage (see Canon 1108), and cannot have conjugal activities without sin. Also your one and only marriage certificate will be signed by a judge instead of a priest and your Catholic marriage will then be a convalidation (see Canon 1160). You can get approval to have the Catholic marriage celebrated in another Catholic parish. Permission for mixed marriage is required, or if the fiance has not been baptised (validly or at all), then a dispensation is required. Also, all impediments must be cleared, and in some cases a couple cannot be married to each other due to them, or improper consent.Can. 1108
§1 Only those marriages are valid which are contracted in the presence of the local Ordinary or parish priest or of the priest or deacon delegated by either of them, who, in the presence of two witnesses, assists, in accordance however with the rules set out in the following canons, and without prejudice to the exceptions mentioned in cann. 144, 1112 §1, 1116 and 1127 §§2 - 3.
§2 Only that person who, being present, asks the contracting parties to manifest their consent and in the name of the Church receives it, is understood to assist at a marriage.
Can. 1160 For a marriage which is invalid because of defect of form to become valid, it must be contracted anew in the canonical form, without prejudice to the provisions of Can. 1127 §3.
CHAPTER VI : MIXED MARRIAGES
Can. 1127
§1 The provisions of can. 1108 are to be observed in regard to the form to be used in a mixed marriage. If, however, the catholic party contracts marriage with a non-catholic party of oriental rite, the canonical form of celebration is to be observed for lawfulness only; for validity, however, the intervention of a sacred minister is required, while observing the other requirements of law.
§2 If there are grave difficulties in the way of observing the canonical form, the local Ordinary of the catholic party has the right to dispense from it in individual cases, having however consulted the Ordinary of the place of the celebration of the marriage; for validity, however, some public form of celebration is required. It is for the Episcopal Conference to establish norms whereby this dispensation may be granted in a uniform manner.
§3 It is forbidden to have, either before or after the canonical celebration in accordance with §1, another religious celebration of the same marriage for the purpose of giving or renewing matrimonial consent. Likewise, there is not to be a religious celebration in which the catholic assistant and a non-catholic minister, each performing his own rite, ask for the consent of the parties.
Can. 1112
§1 Where there are no priests and deacons, the diocesan Bishop can delegate lay persons to assist at marriages, if the Episcopal Conference has given its prior approval and the permission of the Holy See has been obtained.
Can. 1116
§1 If one who, in accordance with the law, is competent to assist, cannot be present or be approached without grave inconvenience, those who intend to enter a true marriage can validly and lawfully contract in the presence of witnesses only: 1° in danger of death; 2° apart from danger of death, provided it is prudently foreseen that this state of affairs will continue for a month.
§2 In either case, if another priest or deacon is at hand who can be present, he must be called upon and, together with the witnesses, be present at the celebration of the marriage, without prejudice to the validity of the marriage in the presence of only the witnesses.
Can. 144
§1 In common error, whether of fact or of law, and in positive and probable doubt, whether of law or of fact, the Church supplies executive power of governance for both the external and the internal forum.
§2 The same norm applies to the faculties mentioned in cann. 883, 966, and 1111 §1.