Welcome marmot! That's really too bad you didn't post a couple of weeks ago. There was a bike show in Toronto last weekend, and they did have some bikes and accessories at very good prices, if you didn't mind the trip.
Good luck with your search, as mentioned, ride all of the bikes and see which feels the most comfortable. I was considering at Jamis Aurora when I was looking for a touring bike, and it is a beauty. What turned me off was that the short wheelbase, I was worried I would be kicking my panniers with every pedal stroke. So that's something to remember about as well.
As per tires for your existing bike, I put Continental touring tires 700x32 on my Specialized Sirrus and toured on it. Continental makes very nice tires, and MEC has them in stock.
http://www.mec.ca/Products/product_d...34374302693841
To save money, check MEC for things like clothing, reflectors, lights, fenders, tubes, bells etc. I would probably get better quality racks that they offer though.