My girlfriend asked me to go to Mass with her, as she does so every week...so I did. I was fascinated and my inherent curiosity had me studying its meaning. As I learned I wanted to continue going because I enjoyed understanding it more with each time. This happened just before Lent and, when Lent came, I decided I wanted to see what it felt like to be a believer, out of curiosity again, so I promised I'd "give up my atheism" for Lent. This meant eliminating all the negatives a lifetime had convinced me regarding religion in general and belief in God in particular. It was a form of Method Acting and I looked at it with anticipatory fun and excitement.
So, for the next 40 days of Lent I prayed at least 3 times a day, thanking God, etc. I went to Mass every week, sometimes more (even on my own!) and I participated in all but the Communion, since that wasn't allowed. During Mass, though, I started feeling left out in that I wanted to experience communion.
After Lent I had this "tugging", meaning that I felt a need to continue going to Mass, which thrilled my girlfriend of course, but I even felt this need while on vacation, something that my girlfriend didn't previously do, until I insisted that I wanted to. Also, praying started to feel comforting to me and so that continued too, even more than 3 times a day as I found myself automatically saying to myself little, short prayers.
By the time the new year started, after 58 years of being an ardent atheist, I started to clearly see that, whether God existed or not, it felt right for me to believe. I enjoyed my Church going and joined the RCIA there, which (while attending the classes) made me appreciate the centering I felt as I absorbed the lessons into my life.
Call it self hypnosis, whatever. I decided to become Catholic. It's my own personal decision and I don't talk much about it to anyone but my girlfriend, now fiance. It's right for me, now.
I never thought I'd marry again, never thought that, if I would marry again, it'd be in a Church. I never thought much about God, unless someone forced me to defend my unbelief. But, here I am.
Perhaps patience, living your life as a Catholic/Christian, inviting an atheist to Mass while later explaining what he saw, and your love will work the miracle you want, and perhaps it won't. It can happen but if it will, it will be his decision.