They are made by Bosch. Go to Bosch (if you have such a shop in Canada), they are cheaper than BMW or online shops, they sell them remanufactured.
OR; probably the cheapest, rockauto
http://www.rockauto.com/catalog/x,ca...EPIsubcategory[936],Mass%2BAir%2BFlow%2BSensor,partGroup,22
or get another used one