OP...I tam saying this with compassion... If she leaves you then you are free, but you cannot now separate and look for divorce just because you are tired of her not being a christian....How does that make God look like? so you are now too good for her? You have been saved by grace not because you are holy...May be just may be God wants her to see "LOVE" for what it is really is...
don't deny her mercy and compassion...you have nothing else to loose than to love her as Jesus Loves the church...if she chooses to leave you you are free but Don't look for excuses to divorce her...
Peace to you. God can save your marriage. trust me, a marriage with a "christian" can bring its own lot of troubles.