Mapleleaf,
The quick answer to how the East German workforce was re-integrated is: it wasn't!
German unemployment is currently running at around 8% (from memory). However, close to the Polish border in former East Germany, some towns have nearly 90% unemployment.
Given the welfare system in place, this causes huge strains on the German economy, which is underperforming other European nations and is therefore close to breaching the terms of the single currency agreement on fiscal deficit.
For more economic/employment data, etc. I suggest you go to the following website:
http://www.economist.com/countries/Germany/
Some content is available only to subscribers, but the factsheets and general data is available to all. If there's a particular article of interest which is subscription only, please pm me.
KP