Crossing Canadian border
where can i get information on my entry and departure dates to and from Canada during a particular period
You can get the information about crossing Canadian border from the Citizenship and Immigration website in Canada, which is http://www.cic.gc.ca/english/index-can.asp or http://travel.state.gov/travel/cis_pa_tw/cis/cis_1082.html. From the websites, you will also be able to check the requirements that are needed to visit Canada.
That might be difficult. Were you detained? Driving over,visiting, moving? You can call border patrol, they might be able to look up plates.