It's not too good if the rook on a1 is not defended. After b4, you could have played a5 immediately. If he plays bxa5, you play bxc5. you get an awesome central pawn majority and he gets crappy doubled rook pawns. If he plays cxb6, you simply take on b4, probably best with bishop, and take on b6 later (won't run away).
In the game, you gave him time to move the a1 rook to safety, after which the a5 maneuver won't get you anything.
http://www.chess.com/livechess/game.html?id=96603135
Could someone go over this game? It's suppose to be bad to push the c pawn like that, but I have trouble exploiting it...