Check out Juniper Farms near Wakefield, Quebec. I have never been a member because I get more than enough from my neighbour's plot and the local market, but many of my friends support them and have nothing but happy reviews. I believe they have a pick-up spot in Chelsea so not too far from Ottawa. Something that intrigues me is that they allow members to pay 1/2 price if you work on the farm a certain number of hours. I can't remember their prices but they were listed on their website last time I checked.
Do you read French? You might also consider the Marche Solidarite in Gatineau. Google it and it will come up. It's not a CSA but rather a coop associated with dozens of local farmers and producers of different sorts. I have been a member for a while now and really like it now that I am accustomed to using it. The advantage with them is that you only pay for what you want and you have access to a wide range of products. The website ordering process takes getting used to though, esp if your French is rough.
I also recently drove by a food coop in Sandy Hill (on a corner a block or two north of Laurier, maybe on Chapel?). I don't know much off the top of my head but I remember reading about it when they were getting started a little while ago and it sounded interesting.
Good luck finding what you are looking for!
Happy mumma to my boys Henny Tom (Nov 30, 2008), Arlo Odie (Oct 5, 2010), and baby SISTER! due mid-Dec 2014.