Sega has opened a small page inside the Senjou no Valkyria 3 official website for the EXTRA EDITION. There is no new information that we didn't know already besides a new trailer and the english names of the 3 new episodes. It looks like the official name is Senjou no Valkyria 3 E2.
The Episodes are called:
·Place where welcomes us always -HOME- Complete (This is the Imca epilogue).
·Where they should be カリサの格言 Carisa Contzen.
·Look up at the sky 空 Kurt, Gusurg.
Details about the 4 DLC pieces that will be included in this edition can be found here.
Here is the trailer:
If you can't watch the trailer here, you can go to the official site and watch it there.
Senjou no Valkyria 3 E2