Short answers, pulled from the story.
The Bzura campaign ended in defeat for the Poles but halted the German advance on Warsaw for several days. Polish casualties were estimated at 20,000 dead including three generals: Franciszek Wład, Stanisław Grzmot-Skotnicki and Mikołaj Bołtuć.
On the night of the 9th of September, the Polish Poznań Army commenced a counterattack from the south of the Bzura river. Their target was the German forces from the 8th Army advancing between Łęczyca and Łowicz towards Stryków.
The German offensive included the 8th Army under Johannes Blaskowitz and the 10th Army led by Walther von Reichenau. Elements of the 4th Army under Günther von Kluge also participated from Army Group North along with Luftflotte 1 and Luftflotte 4 under Hermann Göring.
German casualties are estimated at 8,000 dead during the battle. An additional 3,000 men were lost as prisoners during the initial push while some 1,500 German soldiers were killed or wounded.
Army Poznań was commanded by General Tadeusz Kutrzeba who accepted command over Army Pomorze after their merger on the 6th of September. The main thrust of the Polish offensive involved units under General Edmund Knoll-Kownacki known as the Knoll-Kownacki Operational Group.