Congrats on the new car. Your car has about the same milage and options as mine, so it gives me some idea of what my car is worth (though after subtracting the dealers markup, I'd get killed if I traded it in).
Anyway, the navigation issue you're talking about is with the screen - even if you upgrade the software/DVD, it'll be the same. The problem is that the resolution on the screen is too low - something they improved with the 2007 model, I believe. I've been trying to find a way to replace the screen without replacing the whole unit, which is a costly proposition, but haven't found anything yet.
Enjoy your new car!