I don't have exact % as of yet
But I know Hispanics supported Obama 71-27%...and I'd say probably 80% (or more) of Hispanics are Catholic...
So, you'd probably be quite correct to assume that white Catholics supported Romney more than Obama...but probably by % somewhere around 50-47...that would be my guess...
The bottom-line even there is that even among white Catholics, I don't think Romney got their majority of all white Catholic votes (51%)...