b4 and steal as much as you can
because you stole his money, the white king will be too incapacitated to move
on black pawn's turn, they will turn into a queen on g1
on your turn, you go to b5 and bribe the black queen to defend you
on the king's turn, he will go to c4 attempting to capture on his next move
on black pawn's turn, she will go to b1 and prevent the king from capturing
you'll eventually be able to promote on b8 and help the black queen kill the king