No, you cannot use NW SWU's for CO-operated flights. The SWU's are for NW and KL operated flights only.

You can try to use miles for an upgrade but you should call Continental first and confirm that mileage upgrade space is available before booking your flights.

Since CO just changed their reservation system (January 21, 2009), I believe a NW B fare now matches to a CO B fare. They are both second in line, behind "Y".

-RM