Irish,
She doesn't need to be Catholic, and the dispensation that you have to get to marry her is easy and there are usually no issues if she's a baptised Christian. If she's not a baptised Christian then you'll need a dispensation of cult which is slightly more difficult to obtain.
But she will have to promise to attend a pre-marriage course (it's usually not overly Catholic and it's not a Catechism class). She would also have to promise to not prevent you from practising your Catholic faith and she would have to promise to allow any children to be brought up in the Catholic faith. She won't have to attend Mass or anything, she just mustn't prevent you from taking the kids to church and Catechism.
Each church has its own rules regarding the ceremony. With a mixed religion marriage, most are more than happy to only do the wedding ceremony bit and to leave out the Liturgy of the Eucharist. Some churches are stricter than others with the rule about the bride and her bridesmaids having no strapless dresses, you'd need to check this with your church.
The Code of Canon Law allows this by dispensation only. Here are the requirements for dispensation:
The local ordinary can grant a permission of this kind if there is a just and reasonable cause. He is not to grant it unless the following conditions have been fulfilled:
1. the Catholic party is to declare that he or she is prepared to remove dangers of defecting from the faith and is to make a sincere promise to do all in his or her power so that all offspring are baptized and brought up in the Catholic Church;
2. the other party is to be informed at an appropriate time about the promises which the Catholic party is to make, in such a way that it is certain that he or she is truly aware of the promise and obligation of the Catholic party;
3. both parties are to be instructed about the purposes and essential properties of marriage which neither of the contracting parties is to exclude. (CIC 1125)
I would get in touch with the leader of the church you intend to get married in and work out the best plan for getting your dispensation with that person. I'm a Buddhist so I find this all rather interesting. Best of luck..................