According to Comic Otomegai, the DVD doesn't include a new unaired episode but carries a different version of the episode 16 with some new scenes.
Source: Comic Otomegai
According to bk1 online bookstore, an extra DVD will be bundled with Kimi ni Todoke
manga vol.11 to be released on June 11th. The DVD will include a recap episode, an unaired episode and a video of Kimi ni Todoke live event. The total length of the three will be about 30min.