The 2013 ranking been posted at IPSC Canada web site for a while [1] and RD explained the slot distribution process in the latest Diligentia magazine mailed to members in December. If you see your name in top 20 or so ranking, but haven't received slot email from RD, you may need to contact your SC and check about your slot. Same goes for those members in top 30 rankings and want to be in a waiting list for slots declined by higher ranked members.
Also, USPSA will be hosting US IPSC nationals on the same stages as WS, week after the WS match. It should be much easier to get a slot at that match.
[1] ipsc-canada.org/info.html