Joining the EU has been somewhat mixed for Poland -- for one it has given legitimacy as a higher developing country, given it access to trade and markets that it wouldn't have otherwise had, reduced or eliminated import taxes on its goods and opened it up to foreign investment which is primarily from Germany and France but also the UK
on the negative, it hasn't resulted in money for Polish infrastucture projects - that is being provided by Poland itself, and it ties in Poland too much to Europe -- which is opposed by the more conservative parties here (and note that the present party in power is centre-right and conservative by American, forget about European standards).
however, the Poles distrust Germany and Russia -- it's in their blood to not trust either. and they know that Germany shackled with the EU is better than a marauding Germany (1410: Battle of Grunwald, 1793 partitions of the Polish-Lithuania Republican commonwealth through to 1939-1945).
Oh? Britain isn't in the eurozone either, but they are liable to backing the bailouts. You sure of that? Everyone in the EU participates in the eurozone, even if they aren't in the euro currency. Many other countries not even in the EU participate in the eurozone—you never heard of the "European Free Trade Association", through which Norway and Iceland participate in the "single market" (or "European Economic Area") but also agree to have EU law foisted upon them?
Poland has it's own money, the złoty. They were supposed to join in 2012, but that's not going to happen. They don't have to bailout anyone in the euro-zone as they aren't in it