Sorry that my answer is in English, ich bin in Deutschland nich so lang.
Most Germans don't know anything about EU, so don't listen to those who claim that you need "versicherung für Ausland". This is simply rubbish.
You can use medical services outside of Germany in EU, but ONLY in cases of emergencies. Simply you cannot go to a dentist if your tooth doesn't hurt. But if you are in an accident, the hospital in Poland MUST take you in, even if you are a homeless immigrant. So don't worry about accidents, you will never be asked for the card by ambulance crew.
Moreover, you need a "european health insurance card", which is provided by some German insurers automatically, buit not all: TK gives it (it's on reverse of your medical card), others not always. So if you don't have the blue EHIC card, then get it before you travel. If you don't, you will have to pay for the hospital and then demand the return from your insurer (Krankenkasse).
The system works moderately well. I have used a Polish card in Germany, and now a German card in Poland. In both cases there is a big surprise and a bit of a fear from the side of the doctor, but I never met with big problems.
Finding a doctor who speaks German In Poland will be difficult, so better try with English. Most people younger than 35 do speak at least some English.