What type of information is included in Schengen?
Depends on the country. I'm not sure what Poland is doing exactly (some countries, like France, use SISone4ALL as their national system too), but if you're known to the police, it's likely to come up.
Will I be stopped at the border if she did in fact file some sort of complaint with the police?
Maybe, maybe not. If the police were interested enough in the case to put it on the system, then yes, you're likely to trigger a "hit" on SIS.
I know Schengen can be tough on non EU's.
It's not only SIS that you want to worry about, but the fact that if she made a complaint to the police - this will come up during any future residency applications.
I'd suggest getting hold of your Polish police record and finding out if they want to talk to you about it before trying to cross a Schengen border.