Remember that creatine monohydrate needs a carrier molecule (glucose) to get into the blood stream. I don't think it matters when you take it so long as you get it in between workouts. Some people do a loading phase, but I always recommend to people to take it every day for 2-3 weeks, and then just take it after workouts. If you stop taking it completely, it should take about a month for your creatine levels to go all the way back to normal. I don't think it really matters whether you take it before or after, although theoretically, you might absorb it better after a workout. Personally, I do 5g pre and 5g post when I'm taking it. It's probably a hell of a lot more than is effective, but I really don't care. It's not hurting anything. I believe creatine monohydrate has been shown to be effective in doses as small as 2.3g. I would take...7 capsules post workout if I were you.
And no, the beer shouldn't bother that. Like you said, just stay hydrated. I had 10 beers one night last weekend and I'm still kicking.