Take one donk's stack or go for two?

New to NL 200
Button is playing very off. I have him labeled as "piggy bank" as he is raising and calling with very marginal hands.
MP is X-loose. I don't (think I) want him in this pot really.

Party Poker No-Limit Hold'em, $ BB (6 max, 6 handed) FTR converter on zerodivide.cx

Hero ($354.79)
MP ($458.02)
CO ($736.70)
Button ($112)
SB ($56.70)
BB ($335.35)

Preflop: Hero is UTG with A [img]/images/graemlins/spade.gif[/img], K [img]/images/graemlins/heart.gif[/img]. SB posts a blind of $1.
Hero raises to $10, MP calls $10, 1 fold, Button calls $10, 2 folds.

Flop: ($33) 8 [img]/images/graemlins/spade.gif[/img], 6 [img]/images/graemlins/spade.gif[/img], A [img]/images/graemlins/heart.gif[/img] (3 players)
Hero bets $25, MP calls $25, Button raises to $50, Hero ...

What's my line? Button only has 50 left but if I bet that MP may call with draw. Do I care? Should I push hard to isolate?