He scored 34 goals between January and May 2012 in the second half of the 2012-2012 season - you can find the details here starting with the last. He has since scored another 23 goals in the 2012-2013 season, and you can find the full details of them here. So that brings his total for this calendar year to 57.

Among many other awards, Ronaldo holds the record for being the first player in
a European team to score over 40 goals in one season. So he may even beat that
by the end of the 2013 season, we don't know yet. But judging by his career so far (and he is still only 27) he will probably go on to break more records in future.