1. The marriage performed under the Special Marriage Act, 1954 is a civil contract and accordingly, there need be no rites or ceremonial requirements. Since your would be wife is a Christian the marriage cannot be solemnized either under Hindu Marriage Act or Christian Marriage Act.
2. The wedding ceremony can take place in a church and/or according to Hindu rituals, but the marriage cannot be treated as solemnized unless both of you either convert to Christianity or Hinduism prior to the ceremony. The marriage can only be under SMA.
3. It cannot be registered under Christian Marriage Act unless both of you are Christians.
4. After a religious ceremony in Church or Vedic Ceremony you can marry under SMA.
5. You need to apply to the marriage registrar appointed under SMA for the solemnization of marriage.