Hi Jessy,
Hmmm..... I've been thinking about this one a bit. I don't think we're going to get very far without her parents names, or a more specific location within Quebec.
We might find them on the 1851 Canadian census, if they are still there at that time. Although I can't find a web site that will tell me whether or not British soldiers posted in Canada would have been included on the Canadian census. (I agree with the other people who suggested that her father was likely in the army - serving first in Canada then in India)
The 1851 has just been put on-line at Library and Archives Canada
http://www.collectionscanada.ca/archivianet/1851/index-e.htmlbut there is no name index yet - it is only searchable by place. And since we don't know exactly where they were, it is too big a task to search through the images.
Another possibility - I seem to remember seeing something about children born to British parents abroad (i.e. military) being recorded in a special index? Held at the National Archives perhaps? Maybe someone else reading this would have more info on that....
If there is a way that you can get a hold of Mary Ann's full marriage record to see if her parents are listed, I think that would be the best place to start.
You mentioned the 1881 census - do you have the others? I have found Charles and Mary Ann in 1871 and 1891 as well - if you need those let me know.
If you don't mind, I think I will post a note on the military board about this to see if any of the experts over there can spot her father. The more help the better!
MJP