(The game I should have won) what should I have done??

Plainfield tournament

List of positions:
8
7
6
5
4
3
2
1
A B C D E F G H

Opponent:
KING at b2
pawn b2
pawn c3

Me:
Bishop a3
Bishop a4
rook b6


what do I do.. I was owning him the whole game and some how he wins (at Plainfield) my first tourney,, 3-2 :(!Should have been 4-1!)