Hunting for Mistakes * GÁL, Hanna vs. me

"2kr4/p4p2/8/2b4p/3Nb1rP/5PP1/PPPR4/2K1R3 b - - 0 27"

After White's last 27.f2-f3??
it is Black to move

The game was played in the county team championship, on Jan-17, 2010.
I was the second player and in my time trouble I missed to exploit White's blunder and made a weak move. (It was time pressure on my part, while the opponent had plenty of time...)

Try and guess the move-sequence that wins the game for Black. (please write your solution as a comment to this entry)