It seems to me that your discernment process is not complete. If you are unsure, you should probably give yourself some time. And yes, you do have time. The need for a decision is not as immediate as you seem to feel. You are not obligated to get engaged after a certain period of time dating, but, in fairness to your girlfriend, it might be good to communicate to her that you are in this discernment process, and even slow the relationship down a little bit to give you some space. This may be painful for her, but if she is the faithful Catholic you describe, she will understand the importance of giving you room to make the decision God wants you to make, and she won't pressure you.
I am noticing something of concern in the way you talk about your very difficult situation. You talk about what you are attracted to and what you want:
[quote="TauCTC, post:1, topic:333484"]
I would love more than to live a life for Christ through the priesthood and be a spiritual Father to my community...There is nothing I'd like more than to be a priest, but I would love to call this woman my wife.
But I don't see anything that indicates how you have been trying to discern your vocation other than your feelings about what you like. Attraction to a person or a way of life does not a vocation make.
The question when one is discerning one's vocation is not, "What attracts me?" or "What do I want?" The question is "What does God want?" If the story of Jonah tells us anything it is that sometimes one's calling and one's desires do not always coincide.
Leaving the true Church to go to a denomination that lets you have both things you want would not ultimately help you. In the first place, you are called either to the catholic priesthood, or to Catholic marriage. As an Anglican you would have neither valid ordination nor a Catholic marriage. In the second place, (and please forgive what may sound harsh here) it would be a selfish decision, focused on allowing you to have your way, instead of having to move past your desires and figure out which one God is calling you to. This cannot ultimately satisfy your soul, and, since you know that the Church has the fullness of truth, leaving has the potential to even endanger it.
Bottom line, keep praying, talk to your girlfriend, and get a Catholic spiritual director to help you. And don't leave the Church. People who tell you to do that are thinking as the world thinks instead of challenging you to think as God does.