Confused on Turn, Stars 10:15 $11+R

[Chobohoya]

I've got about 11k at the start of this hand, and villian has me covered by a good bit. He just moved to the table a few hands ago. Blinds are 100/200.

Villain limps UTG, folded to me in BB, I have ATo and check. I didn't know what to make of his UTG limp, I would normally raise, but didn't here for some reason.

Flop comes A [img]/images/graemlins/heart.gif[/img] Q [img]/images/graemlins/club.gif[/img] 6 [img]/images/graemlins/heart.gif[/img]

I bet 400, he calls.
Turn (t1300) 2 [img]/images/graemlins/heart.gif[/img]

I bet 600, he raises to 2200. I feel like I ought to fold here, but I really think he could be screwing around with me. What's my best plan?