Noxy
When you go to the movie with her be aloof.......like you'd rather be anywhere but there. Don't tell her about the bartender be very mysterious......tell her you want to start having fun and enjoy being single......chicks hate that. They want you to be single and miserable.
If you care too much for them they don't like that......they want a man with a little edge to them.
Also the bartender at work....unless her boyfriend is a good friend of yours work that as hard as you can. All is fair in Love and War. Hopefully she'll star banging you and keep the boyfriend. 3 years ago when I was still single I was dating 2 girls who each had boyfriends at the same time. I was the other man for 2 different girls......no responsibility whatsoever. That should be your goal right now in the short term.....long term you'll find many more girls introvert or not. Trust me.