5/10 live hand, nut straight on paired board

[foobar]

Hey all,

I was sitting in what turned out to be the best live 5/10 nl game of all time at Mandalay Bay last week and this hand came up early in the session. Thoughts on my river play are appreciated.

Relevant stacks:
Me - ~$1600
Old Man - ~$1750
SB - ~$700
I'm in the BB w/ 45c

Old guy in MP limps as do CO and Button, SB completes, and I check. $50 in the pot

Flop comes 2h 2d 3c.

I lead for $40 and get called by Old man in MP and SB.
As I said, hand was early in the session, but Old Man in MP was a local and hadn't gotten out of line. SB was absolutely horrible, and we later found out that he was just some rich dude that saw Hold 'em on TV and wanted to give it a try (He left after dropping 3K in about 50 minutes). Anyhow, $170 in the pot

Turn comes Qd [2h 2d 3c] and it checks around. $170 in the pot.

River comes Ac [Qd 2h 2d 3c].
SB leads for $100 and I make it $400 straight expecting Old man to fold and SB to pay me off with any two cards.

Unfortunately, old man foils my plan by pushing in for another $1300 or so on top. SB calls off the rest of his stack.

What's my action, and why? Is it close?

Thanks