According to Bill Hunt, editor of TheDigitalBits.com website, who attended the cast & crew screening of the finale, these are the episodes that will be extended on the DVD release, and by how long:

4x11 - 'A Disquiet Follows My Soul' - extended by ~10 minutes
4x18 - 'Islanded in a Stream of Stars' - extended by ~20 minutes
4x19/4x20 - 'Daybreak, Parts 1 & 2' - extended by ~20 minutes

That will make the finale about 2:40 total, not including commercials of course (which would have bumped it up to about 3 and a half hours had it aired uncut and in 1 part). And the complete series DVD should come in July, with Season 4.5 coming a little bit earlier than that.