No knowing the whole story, but if she claims to be more spiritual than religious, and goes to church, I would say she is religious. And for me that would be a deal breaker.,
It's difficult but if someone is spending time in church and it's the only time of the week set aside for you then I'd be looking to back out before you got in too deep. I think it's not impossible to have a good relationship with someone spiritual or mildly religious but if going to church by herself is more important than being with you then that says something.
You're always going to be in a relationship with a believer. Is that what you want?