Okay, hate to break up the party

but I have been apart of a huge mess like this and the best advise is Tim's. Your emotions got the best of you (as what happened with a former President) and the best you can do is let this pass. Let things calm down, talk with the group later with an apology ( your vocablary may have been more than anyone had bargined for!
As Kenny Rogers say-
You got to know when to hold 'em
Know when to fold'em
know when to walk away
know when to run
Sometimes a poker game can be related to a PTO meeting!
In regards to by-laws. Again, an angry exchange of words like that may be enough to make some wonder if this happened for this issue how would she handle other situations?
I wish our former President would have walked away after she offened the new Principal. She apologized but the relationship was strained the rest of the very long school year.
I am glad to hear that you were able to mend things with the [parents, usually you hear the reverse!