Sounds like we'll be in the same class ^_^
As for the convention, i wouldn't worry about it too much. They make a big deal deal about it over the phone but when I asked to be excused the office lady said every year people don't go because they visit family in India or somesuch, so it can't be THAT crucial. I asked around here earlier and the vibe i got was that it's more to give you and your parents info on the school, Poland, etc than to do further examination of your worth. I'm half sure the interview there is just so they can negate claims that you're accepted without any formal interview whatsoever.