Draw when heads up?

[wizard]

You are now playing for 1st and 2nd in a Full Tilt multi. 1st is about 950 and 2nd is around 650. Your opponent has played sound but is probably a little passive. You have just doubled up twice and have around 100K to his 150K with the blinds at 2000-4000 + antes.

You are 1st to act on the button and get AT clubs and raise to 16000 and get called. The Flop looks pretty good with Qc, 9c and a small red card. To your surprise, your opponent bets out for 25000 onto a pot of about 35000.
Your Action?

Based on his prior passive play there is no doubt in my mind that he has a Q and will not lay down his hand. For this reason, I chose to call but wonder if fold might have been better.

The turn was a red 8 so I have improved my outs from a probable 12 to a probable 15. My opponent now decides to push.

What now?

Results are not important but will follow for the curious.