Just need some quick advice !
There is this woman at work, who came to my party a few weeks back, we had a great time and ended up grinding at some club for a couple of hours, nothing came of it, as i had to go back home to tend to a sick mate. Well anyway i work once a week, and we talk, but usually its a very busy stressful environment (casino) so we can't communicate very well.

Anyway she does present me with ioi's but of course being at work makes it harder. I invited her to come to a gig with me, but she was working that day, so i just left it as that. How can i ask her on a date next, or escalate the situation, I've been holding distance and demonstrated higher value, but haven't made another offer for a date yet, because I'm not sure how to work this. Any advice ??

Ask her when she's working. Pick a day when she's not working. Invite her somewhere casual and relaxed so you can actually get to know each other. Be specific with the day, time and place.