Connie,
We lived in Atlanta for years and let me put this in perspective for you... Every time my wife goes home to the States, her last meal before we head to the airport on the return trip is always BREAKFAST at Waffle House. I just need to ask which one.
So don't look for an American breakfast in Italy. It is mostly coffee and "cornetto" for breakfast, followed by a big lunch!
Even most McDonald's in town do not serve an American breakfast (I have a craving for a sausage & egg biscuit!). You can get an Egg McMuffin at a few in-town McD's (like the one in Termini Station) but most sell an "Italian" breakfast - What's the world coming to??
Some hotels do feature an "American breakfast" but even these are weak imitations of what you're used to. Whenever we head to the UK, we load up at breakfast time!
You can get yogurt at a few places (cafe's) and at ALL grocery stores. In fact, the varieties and amount of yogurt in grocery stores here is astonishing!
Ciao,
Ron