I know I need a passport and a visa,
No Visa is required. Just a valid passport.
and an estimate as to how much money I'd need to stay. The longest I'd be staying is a month.
Where do you plan on staying? Hostel-Hotel-Host Family?
If you'd like a host try here:
There may be someone nice enough to give you a room/bed and assist you with translating or getting around. You do need to learn how to purchase tickets for the bus. I'd also brush up on your Polish :) It will help alot. Just keep in mind that it may be frustrating to get around, but be patient and don't lose your cool. People can easily avoid you if you're irate :)
I'm flying into Poznan, so I would assume whatever international airport they have there. I don't know the specific name of the airport.
Poznan airport used to be an airforce base. It's really small, but friendly.
Ok I see you chose the Hostel :)
I have a little info and pics here: members.virtualtourist.com/m/a3382/
I hear the Frolic Goat is a nice choice. There's also the Dizzy Daisy. Let me know what type of music you listen to and I nay be able to point you in the right direction.