[elindauer]

Questions: what range of hands will he 3-bet? What is your hand range on the river?

I need the answers to these questions to go much farther, but my guess is that your range is fairly wide and AQ is near the top. I'll also guess that AQ beats lots of hands that he could have reached the river with, so a 3-bet is going to be at least in the mix for this hand. This probably coincides nicely with your intuition and is exactly why you're not sure of the answer... the answer is both.

good luck.
eric