Shit ok this might turn out good for you but I'd watch out she might get wasted and fuck some one else you should hang one on one
She obviously likes you. It went from helping you with work to going to a party with apparently no fuss from her. Just invite for a movie, get comfortable with her (preferably before the movie or as at least on the first few minutes) and make some sort of move mid movie like unzip your fly and pull out your cock. She will know what's up and hopefully proceed to sucking. If she says no then kick her the fuck out.