Episodes 14 - 25 of Fate/Zero To Be Aired in Spring 2012

According to Newtype magazine, the second half (episodes 14 - 25) of Fate/Zero will be aired from April - June 2012. There will be a break after episode 13 airs this December. The Blu-rays of the series will be released in two box sets instead of the conventional monthly releases of two three-episode volumes.

Source: Scan of Newtype

Fate/Zero 2 on MAL