Don't wait a week to ask them out.
Strike while the iron is hot and ask them out sometime during the 30 minute party conversation.
I'd also second the join the club and get a hobby thing. It's one of the easiest ways to meet someone (i.e. the shared interest). I am sure you could be painting your Warhammer 2000 figurine only to look up into the eyes of another Warhammer enthusiast only to find she is looking right back at you.
