According to Fujimishobo, an OVA of Date A Live will be bundled with the ninth volume of the original novel. It will be the unaired 13th episode of the TV series and will be released in December.
Date A Live anime official website
Date A Live Trailer
The first episode will be first aired on Niconico on March 30th.
Source: Fujimishobo
Date A Live OVA on MAL
