I'm no tax guru, but as far as my understanding, you can only claim the loss on your property once you've realized the loss or gain ie if you've sold it or are moving back into it amoung other things.
As for the loss, it would be a capital loss and thus not eligible to offset your other income(unless it was a capital gain of some sort) but is eligible to carry forward to offset future capital gains.
As for CCA, Im sure you can refile old returns, how far back I'm not sure, if its like the disability tax credit it's 10 years.
Now someone in the know can tell me how wrong I am so I may be wiser.
Oh and i believe you can only claim CCA up to the point you're break even on the rental.