How do you get Canada's historical weather system maps?

I need to get the systems map ( a weather map showing current systems) for the 25th of march 2011. The only keeps the current one. If you don't know what I mean by weather map you can see todays here: If you know where I can get one for the 25th I would really appreciate it. (I am in Canada, so one that shows Canada would be most relevant to me, but any would help.
thanks in advance 

Have you tried the Environment Canada National Climate Data and Information Archive at ?  The link below should get you to the historical radar page.