I would have played it like this:

Preflop I wouldnt open with ATo at UTG+1, I only play ATo in late position ( and even then I most of the time do it with a sigh knowing that I'll probably will regret it ).

Flop: fold.
Turn: Raise - if BB reraises, get out.
River: Why raise here in the first place if you didnt raise on the turn?