Passport troubles

I am here on an ancestry visa. Last June I extended it, so I now have FLR. I am planning to go for ILR in June this year.
My Canadian passport is going to expire in March. As I was getting things together to get this renewed, I realised that I need a citizenship certificate from Canada to get the new passport. I had one, of course, to get the original passport, but I never dreamed I would need it again and I put it in a 'very safe place'. Now I can't find it.
Turns out it will be at least 10 months before I can get a new one. In the meantime my passport is expired.
I really need to get ILR in June as my son is 17 now and needs to get his. In other words I need to get mine, so he can get his on my coat tails before he turns 18. It would just make it all so much easier.
Now I fear I am in trouble. Any thoughts?
I want to travel this summer but if the authorities have my expired passport (Canadian) can I get back in with just my card (FLR) and my American passport, which is valid?
Of course my original visa is in the Canadian.

I think this is the link you are after:

Urgent need for a citizenship certificate (proof of citizenship)

http://www.cic.gc.ca/english/citizenship/urgent-proof.asp

Hope that helps you with the first step in getting this sorted.

Thanks! I'm looking into it as we speak.

Were you able to expedite the citizenship certificate to sort the situation?*

* grammar edit

It's really worth it to expedite it in an emergency, if possible. When I applied for mine under regular conditions, it took me ten months to get it.