They also state that it's "extremely likely" that the Season 4.5 DVD and Blu-Ray sets will be released on the same date.
All of these sets are available for pre-order on Amazon.com. The "Complete Series" is listing for $195.99 for the DVD set and $244.99 for the Blu-Ray set on Amazon.
NOTE: No mention is made of the upcoming Sci Fi (Syfy) Channel television movie "Battlestar Galactica: The Plan". I'm assuming that the "Complete Series" sets won't include that movie. The news item doesn't mention "Razor" specifically but I'm assuming that TV movie will be included in the "Complete Series" sets. I'll update this when I get confirmation either way.