yes, a couple of things have happened in between Break-out anc Civil war, but you can skip over it if you want. There's a billion things out there to read, you'll get around to everything you're interested in soon enough, there's no rush to get the things from inbetween Break Out and Civil War
The only thing that's out right now that you should probably pick up are Civil War #1, and New Avengers: The Illuminati special. The "Road to Civil War" books ARE NOT NECESSARY. They're just there if you want some more depth to the story, but you'll be 100% AOK if you skip them all. Never get suckered into thinking you need to get every book that ties into a comic event.
But you also may wanna pick up this and next month's Amazing Spider-Man....
Civil War: Frontline is not necessary to read, it's just there if you're enjoying the story and want some more depth to it. I would say if you're going to read ANY Civil War tie-in, this is the book you should look into first.
I'd also recomend the Young Avengers/Runaways miniseries which ties to Civil War. These are the two newest Marvel superhero teams, and their books have just been fantastic, and this is the first time the two groups of teams are meeting up, it should be a blast.
we also have an Official Recommendations Thread here which should show you some awesome books you may wanna look at
http://www.superherohype.com/forums/showthread.php?t=186190