GMO. Yes many gmo foods available and more coming. Cheerios just changed to non gmo due to demand of consumers.
Yes. At least 80% of processed foods contain gmo. Presume all processed foods have gmo's unless labelled organic or gmo-free. Most corn, soy, beets/beet sugar & canola oil are gmo if not organic. Dairy, eggs & meats that are not organic come from animals fed gmo. Most restaurant food is made with gmo ingredients, esp. If cooked in oils. See http://drrandybaker.Com/2013/04/22/organic-food-diet/.
It's hard. My suggestion is to read labels, aim for organic foods, and cook from scratch. In the U.S., it is not yet required to label all foods as gmo or not. Plus, you don't know if gmo ingredients were used in the processing of foods or as feed for the meat you buy. But you can get gmo foods with some work and diligence.