Might be a bit long.
A few weeks ago, I met this girl. We're both doing a postgrad degree at a university, but I've been here for my undergrad, so I know the place. Me and a few of my friends went to one of the fresher's parties. Although nothing major happened, the girl did seem to show at least some interest, posing with me (and not the other guys) to photos with her arms around me, etc.
A few days later, I got this special invitation for a pre-premiere screening of a movie for 2 people, and asked if she wants to come. It was kind of last minute, so I wasn't really surprised that she couldn't come, but I still assumed that it's an IOD/flaking/whatever you call it, and thought that it's pretty much over. The next day, however, she started a conversation with me on facebook, and it seemed everything is still good, and it continued for the next week or so.
Yesterday, there was this other party at the university bar, to which we both came (technically not together, but she knew i'll be there). For the whole night I pretty much exclusively talked to her (btw, this feeling when you talk to the hottest girl in the whole party, and nobody even tries to interfere is truly amazing

). The problem I have is that I run out of topics for conversation, so there were a few moments of awkard silence. Also, even though I know the theory of pick-up, I find it hard to put it in practice face-to-face, and I didn't really (however, according to my friend and another female girl, she did seem to enjoy herself. She also had plenty of opportunities to talk to other guys, but she didn't and always came back to me). Anyway, she agreed to go with me to a similar thing next week, and she also wants to play tennis with me soon (yea, random).
What I didn't expect was that after I got home, she texted me saying "Good night! Not sure about monday, but looking forward to tennis

". She didn't really have to do that, surely, that's an IOI? Of course, I'm gonna do something about it all and continue to try.
The most important bit of the story, however, is that she has a boyfriend. Although they've been together for less than a year, it seems it's quite serious, she actually moved in with him last week (although she did say that she didn't really have a choice). I know the straw man technique, and as suggested, I just keep ignoring the fact that she has a boyfriend. I'd continue with it, but I'm afraid it might ruin everything. Also, her boyfriend does really seems like a nice guy. I know it's not really a PUA thing to say, but I do believe her bf is better looking and more interesting than me. I have no ethical problem in stealing her from him, but I have a problem understanding why would it even work.
I know that women are illogical, but that's just too confusing. I'd like to continue gaming her, but as I said, I don't want things to get awkward. After all, I'd rather have her LJBF me than hate me.