Yes, Channa would be the easiest answer - if the name is Jewish at all. If this is right, you can ask: Where did the second N come from? The verbal root of Channa has in fact two Ns (chanan, Chet-Nun-Nun, "to be gracious, show pitty"). There are a number of biblical names with the two Ns like Chananya,but they are all masculine. But if the name is Irish, why should it be Jewish?