If you have a legit reason as to why you broke up, stop talking to her. If you keep seeing her, you'll keep reopening the wound, so to say. Rip the band aid off quick and move on! In the short run it'll suck, but you'll get over her a lot quicker if you swiftly and surely end it, as opposed to drawing the whole process out by seeing here every so often.
I really like this girl and work. We have the same interests, taste in music and all that shit. Stoked on that, but not stoked on it being a work thing. They give zero shits about relationships and stuff, but if I were to try and make some kind of a move, everyone will know about it. Also, i'm awful with girls and this kind of stuff so the only plan I have is to just ask her to chill sometime. In itself is an easy enough thing to do, but like I said I suck at stuff like this.