Misty,
If you plotted the relevance of the NDP on the Canadian electoral map, you might note that even with their current bump in popularity they are less of a foce than they were under the leadership of Ed Broadbent. They are nothing more than a protest party at best and enjoy a limited source of popularity only in the midst of a leadership void of the other parties.
They do not represent any kind of trend change in Canadian politics but enjoyed only a temporary bounce in the wake of the abject failure of the Liberals under a most uncharismatic leader.
Make no mistake, Canada does want to lean left or right but holds fast to the centre. As the Liberals reached out for greater support from the left, they lost votes to the right just as the Conservatives did when they reached too far to the right.