You said:
"...This is correct. I first heard her name here on Freerepublic, mentioned by a Polish FReeper..."
Sorry, but this is a shame. Steinbach is well known inside the politicallly informed German circles although she has no real political influence. I would estimate that maybe 20% of the German population know her.
Anyway it is quite probable, that the center of the expelled will be buildt, since Steinbach and her association are the core of the CDU. Angela Merkel is supporting the center because she wants to win elections. This will lead to some confusion within the Polish-German relations, but we all will survive it.