The best place for you to try is the Low carb grocery which is currently in markham, but I order online a lot and its usually here the next day..
They have a huge selection. I have had good luck with the macaroons, if you think she would like that, just b/c they arent so hard like many other boxed cookies can be.
I haven't found a bakery in Toronto yet that makes a good homemade no-sugar-added cookie (my spouse is diabetic, so it's something that I would keep in the house if i could find it!) If anybody out there has a bakery suggestion, I'd be interested too.
Of the grocery store brands, many of them taste like cardboard, but Voortman does a pretty good job of making no-sugar cookies that taste about the same as their regular versions...but they're not 'special' cookies, just your run of the mill packaged stuff. They make a chocolate covered peanut butter wafer cookie that I would say is the best of that bunch.