Finally saw your amp... Not sure how I missed it initially...
The amp you have is a 4 channel and puts out about 60 watts per channel. Bridged it does around 150 watts.
Now you can run all 4 speakers off the front two channels of the amp, bridge the rear two into one channel. Bridged, the amplifier can only see a 4 ohm load minimum. So you need either a single coil subwoofer at 4 ohms, a dual coil sub of 2 ohms per coil wired in series or a dual coil sub at 8 ohms per coil like the Dayton wired parallel.
Another smaller option
Another option is, Do you have access to some wood working tools? A table saw or circular saw? a jigsaw or router? Because you can pretty easily build a simple sealed enclosure for about 25-30 bucks. Nothing fancy but serviceable. being in Montreal or close, could you drive down to Burlington Vermont? Have something shipped to a UPS store there? I only ask, because I fly to Burlington when I travel to Montreal for work so know the area somewhat. I know there are duties and such but surely a sub enclosure would not be seen especially if you "installed" it. even without the sub in it
You can also try the bravox subs on clearance.
Save even more money. I don't have experience with them but the money seems cheap!