I haven't tanked as a bear for a while, so I can't give you any specific advice, though to my untutored eye your gear looks more than adequate for heroics. You have a few cheap enchants missing - chest, gloves, etc. you could fix up, but largely I think you're on the right track.
Where are you finding trouble? Are you making adequate use of CC on multi mob packs? How geared are your healers?