Is this still the case ?
Still the case. In fact, 2.4m is really needed in Warsaw these days.
is there not such a thing as a Signal booster that i could use ? or an other trick ?
Nope. The signal simply doesn't extend that far. BBC is on the so-called "spot beam", which means it's aimed at the UK. You can get away with 2m in Western Poland, but 2.4m is the minimum in the east. Some people say that 3m would be safer, but I think 2.4m is enough. Be warned that you might need permission to put up a large dish.
If a 2m Dish really is required, dose anyone know where i can buy 1 ?
diomar.pl/anteny-satelitarne-do-3m/ for instance.