I would suggest that you use the parser program:
Advanced Combat Tracker!
Its an amazing parser that will analyze the fight right down to the incoming dmg breaking it into a pie chart for you.... and lots of other cool stuff.
It also includes a "Timer" portion which will watch your log file for whatever you specify and then give a count down timer both as a visible clock and a audiobal ding! Gives warnings and all that kinda coolness!
Check it out - its deffinantly the best one out there I have seen.