Erica,

You should meet with the parish priest where you would be attending or getting married.
You would likely join the RCIA program to complete your initiation into the Catholic faith. Since you are already baptized, you would receive your other sacraments at the conclusion of the program.

It is very gracious of you to accept the faith for your marriage's sake, but it will be even better when you accept it for your own sake and your own desire to know God more and develop a personal relationship with Him in a new way. I promise you, you will not be disappointed.

Peace and blessings,

Bob Kirby

Dear Erica,

You said:
My parents had the same problem: my father was a Catholic and my mother was a Christian. My father had me baptized so I am baptized but a Christian. I don't know how this works and we need help.

You have a misunderstanding of the words Catholic and Christian. The word Catholic means according to its totality so the Catholic faith is the Christian according to its totality.
It represents all of what Jesus wants us to believe as Christians. As Catholic Christians we recognize the valid Trinitarian Baptism of other Protestant denominations but they only believe part of what Jesus wants them to believe. So for short:

• All Catholics are Christians, but
• Not all Christians are Catholics . . .
  
  though that is what Jesus calls us to strive for through proper evangelical outreach.

Seeing you may be preparing to take RCIA classes in the near future, I would encourage you to consider buying a cheap copy of the Catechism of the Catholic Church to learn everything we believe as faithful Catholics.

Under each boxed format for the Catechism you want, you will see, below the box, an option to buy a used version, which many times, is not really used but close to new.

Mike