Overall, Germany has generating capacity far exceeding power demand. Even after those nuclear plants were switched off in March 2011, Germany still had around 100,000 megawatts of conventional generating capacity online, compared to only 80,000 megawatts of maximum power demand for the year.
At the beginning of 2011, Germany had a dispatchable (i.e. not including solar and wind) power generating capacity of 93,100 megawatts, and roughly 8,000 megawatts of that was switched off last March. According to the German Association of Energy and Water Industries (BDEW), Germany exported 90,000 megawatt-hours net per day on average in the six weeks leading up to the moratorium on nuclear in mid-March 2011, whereas starting on March 17, 2011, the country began importing an average of 50,000 megawatt-hours net per day.
To the east, more power might be imported from the Czech Republic, but not because of any electricity shortage in Germany. Rather, the German power market buys conventional electricity where it is cheapest. Countries like Poland and the Czech Republic are not complaining about having to prop up the German grid after the nuclear moratorium. On the contrary, they are mainly concerned about wind and solar power surges from Germany offsetting their own production of fossil and nuclear power.