Heh,
Been to Krakow & Warsaw recently. You've booked now but would of recommended Krakow instead, anyhow... Don't bother going to the so called irish bar 'Patricks', they are rude & ignorant in there and there isnt even an Irish person working there. There is another small Irish pub there. I can't remember it's name but its really good, its beside 2 nightclubs.
Be careful if you go to any strip clubs. I met a stag group from Cork over there & 3 of them left the strip club early & moments later a car pulled up & 3 people jumped out. They ran & the people got back into the car & chased them up pedestrian streets and everything.
Another stag group i met from England, they were a good laugh. One night they got jumped by about 12 Polish guys when they were going through the underpass/subway. Not to put you off or anything, but just watch out for each other.
I personally had no trouble & i was out till all hours & in different clubs. The Polish people are really nice & you will have a great laugh.