1st, don't drive it until it is fixed, you can burn up your exhaust valves that way. Seems to me you have two possible choices.
1. Check with the salvage yards in your area. Here in the states we have yards that are 'networked', if one doesn't have the part you need they can check around the country to find it and have it shipped over. Not sure if that is an option in Canada?
2. Remove the manifold and thake it to a good machine shop to see if it is possible to repare it. Some cast iron manifolds can be welded and placed back into service.