A Defensive Puzzle

SJFG
SJFG
Aug 5, 2013, 2:25 PM |
2

In this position my opponent just played the shocking 19...Rxb7?! which seems to give a rook for a bishop.  How should I respond?  The first move is easy.  The second move is not as easy.

If you find any alternative moves please tell me.

Note: Click move list to see some variations of other moves that don't work for white.