Short answers, pulled from the story.
The Red Army began its offensive across the Narew River on the 12th of January 1945, and the main fighting for Berlin concluded on the night of the 2nd of May 1945 when most remnants of the garrison attempted to break out.
Soviet forces were led by Zhukov with the 1st Belorussian Front advancing towards the east and north-east while the 1st Ukrainian Front pushed through formations of the northern wing of Army Group Centre.
The sector where most fighting occurred was the Seelow Heights which served as the last major defensive line outside Berlin and lasted four days from the 16th until the 19th of April.
Declassified archival data gives 81,116 Soviet dead for the operation including the battles of Seelow Heights and the Halbe with another 280,251 reported wounded or sick.
Hitler committed suicide in the afternoon of the 30th of April 1945 after Weidling informed him that defenders would probably exhaust their ammunition during the night.