NL100, howto maximize hidden quads

[veryblind]

NL100, 2/3 blinds. Average loose table.

After getting extremely lucky on the flop and turn, how do I maximize this hand?

UTG+1 has about $300
UTG+2 has about $350 and is extremely loose
MP2 (Hero) has about $450
CO (villain) has about $400 and has shown a lot of aggression (not sure if he's playing real hands or not though)

Preflop: UTG+1 opens for $10, UTG+2 calls, I call with 4 [img]/images/graemlins/diamond.gif[/img]5 [img]/images/graemlins/diamond.gif[/img]. CO raises to $30, UTG+1 calls, UTG+2 calls, I call

My initial limp is questionable but I figure I could play trickier with deep stacks in a fairly loose passive game. I'm pretty sure I'm behind when CO raises and it gets called twice, but by then I am getting 5-1 on my money and figure my cards are live.

Flop ($120): 4 [img]/images/graemlins/spade.gif[/img]4 [img]/images/graemlins/club.gif[/img]2 [img]/images/graemlins/diamond.gif[/img]
Checks to CO who bets $40, folds to me, I call

I thought about leading out and letting CO raise in case he has a real hand, but I felt he will likely fold if I lead into him plus I was fairly certain he was going to bet and I rather have one of the other 2 players check/raise commit themselves.

Turn ($200): 4 [img]/images/graemlins/heart.gif[/img]
I check, CO bets $50, I minraise to $100, CO minraises to $200, I push, CO folds

I really don't think anyone can put me on a 4 given the mathematical improbability of that event plus the preflop action.
I was hoping he had a big pair and would call my all-in. Given what I know, I probably should have just checked and let him catch up or bluff all-in river.

But not knowing what he would do before I push, what is the best line here?