If I wanted to add a subwoofer to a TORII jr how would one go about doing this, or can you?

If you get a sub with speaker level inputs you can run your speakers and the sub from the amps binding posts.

Something like this can be used with a sub lacking speaker level inputs:

http://www.crutchfield.com/S-WkhpVxpbGyy/p_543ADP12/Russound-ADP-1-2-Speaker-lev...

Palomino does something like this - he's picked up a small rackmount amp that has some built in basic DSP, so he can crossover the input with a low-pass filter and dial it in to match his main speakers. I was really surprised how good this sounded and how well he was able to integrate this setup. I've tried it in the past and didn't like the sound, but technology has come a long way in the past 15 years since I've tried this. Maybe he can chime in on what amp he's using - I'm tempted to get one myself as I'd love to take one of my big sub-woofers that can go down to 10hz and augment my MG944

You could also get a plate amp made specifically for these kind of setups, where you can take the speaker outputs and run one pair to your speakers, and one pair to your plate amp. From there it's pretty much like the above rack mount amp where it has built in crossover and phase settings you can tweak to better integrate with your main amp.

Both of these setups are pretty slick, because you aren't tied to any particular main amp, sub, or speakers. It's a real way to integrate any sub into just about any setup - and a great tool to have in your audio setup.

There are also more complex setups, that take measurements and help setup the subs crossover and phase and all that, but they cost more and take more effort to get into - but can be much better integrated once you figure it all out. That's a whole different discussion though, and I might write an article on it once I find my microphone and explore this path a bit more.