Hi LeAnn!
I always told my sons that whining hurt my ears and I couldn't hear them when they whined, so they needed to use their "normal" voice. If the whining persisted, I would turn to my son and say, "I'm sorry. Did you want something? When you can speak to me without whining, I'll be able to hear you." My oldest figured it out quickly; my youngest took a bit longer, to the point where I'd send him out of the room to count to ten, take a deep breath and try again.
Interestingly, this same technique works well on the high schoolers I teach, although rude attitude is more common than whining, although I still get that. For that reason, I disagree with "cutting some slack" because your husband just left for Iraq...bless you for your sacrifice, btw. Life doesn't always go our way and whining doesn't solve anything and, in fact, often makes it worse. Food for thought...
Find your catch phrase and stick with it. Add to that praise whenever she uses her normal voice and I think she'll come around.
Good luck!