Wow.....some questionable advice in this thread.
I have spent alot of time hunting and guiding in Ontario and other parts of Canada for bear and big game, as well as in North Carolina and in the Western USA. That being said,...I would laugh in your face if you showed up with a .243, .260, 6.5x55 ect. I usually know a year in advance what my clients are planning to shoot, what loads they will use, and what gear they bring. I check back with them throughout the offseason to ensure they are in shape, studying bear judging, and shooting often. I think for bear (300-600lb live weight) a 7mm-08 is a MINIMUM, and I would prefer that you have a .30 cal with well made heavy bullets. I want that bear down right now!
There is nothing wrong with the rifle you have. Try the 180gr managed recoil loads in your .30-06. You can also have weight added to your stock, and/or add a better recoil pad. If you have a spare mag that you don't mind destroying, pour it full of lead and then load your rifle like a single shot. There are plenty of good aftermarket stocks out there too. McMillen and B&C are two of my favorites.
Got a friend that handloads? Try a good .30 cal bullet at aroung 2400 fps. Mild recoil and still plenty of power to break a bruin down.
You DO need a scope with good magnification as you will want to examine your bear and judge its size prior to taking a shot. However, most shots WILL be at less than 80 yards. I would be just as happy to see you show up with iron sights and good 10x50 binocs as a 4-12x50scope.
If you must buy a new rifle, and it sounds as if you want to anyway, I would get a fairly heavy .308 or .7mm-08, (Ruger Hawkeye, Remington VTR, ect) and put a good optic with mid-range power on it. (3-9X40)
Perhaps the best thing you can do is spend a few hours at the range with a shooting coach working on your form and practicing with the rifle and load you will be shooting. You may find that that .30-06 doesn't kick as hard as you remember. Not to make you feel bad, but my 105lb wife shoots very hot handloads out of a 7lb .30-06. She practices often with a .22lr and lighter loads in the '06. We shoot more than most people due to having a range in our back yard.
I hope you have a great hunt and take a biggin!!!
T2E