You can try canada411.com and telus.net for phone directory listings nationwide. That'd only be good if she has and lists her copper wire telephone service under her own name (e.g., she may not have a listed phone number if she shares a place). It's not uncommon for those with land lines to unlist their numbers. If they have cellular phone service only (increasingly common), they probably won't be listed either
It's also not uncommon for people to move, especially out of province so extend your search to all provinces and territories.
Good luck in your search.