Expiring passport, will be let back in for a few months?

I stupidly tried to take too many boxes in at once off Amtrak and this got me on their file. I was let in for one month under the condition that I show up at the office and present a document and leave the country, but according to that officer if I can show a bank statement, return ticket and forwarded mail in my name from the US I can try coming back in on the same day, even.

The thing is my passport is limited validity 1 year, as a replacement for the real one I lost. It expires Feb 26 2010.

If I show them a return ticket for, say, Feb 15, to leave Canada before it expires, will they let me in until then? I was hoping I could then mail off the passport and get it renewed (takes 2-3 weeks) and then apply for a visitor extension once I get it back, or leave and come back once more if need be in order to get the normal 6 month entry status.

I don't want to be stuck in Seattle waiting for a passport, before trying to re-enter again. Any thoughts?

Thanks!