Materials: - DVDs of several TV programs with multiple seasons (make them subject relevant if she has a specific subject-matter goal) - Several regular talk radio/podcasts - You. Apparently, you know English. Stop speaking to her in anything but English. Just stop.
Method: - The goal here is to bludgeon the language faculty of your wife's brain with English. It'll feel kinda uncomfortable, but you want to create an experience that so surrounds her with English that the brain is forced to do work it's already good at – that is, figuring out language. - So, every day, listen to talk radio. It creates the same experience as being dropped into a conversation in a foreign country where you don't know the language. She just needs to try to follow the conversation. This has the added benefit of not taking place in a bar or cafe, with a lot of back noise. Encourage her to take note of words that get repeated a lot, to look them up, and to listen again, but don't waste her time with exercises that answer questions about the content, b/c the content is irrelevant. - Next, pick a TV series and start watching. Have your wife choose a character to 'follow'. She is to repeat everything that character says, in as close to the same accent as it was produced. Most TV shows are about 30-60 minutes, so have her do this with a few shows, just make sure the shows feature a few characters that do a lot of talking, so that she get's more practice. - Lastly, go out together, a lot. Meet people. Language exists between people first and foremost, so the best way to build on her practice is in the field. Beforehand, she can prepare the 20 or so important things that she might want to say/talk about, and discuss them with you. Then, take her to an event to meet people and abandon her to fend for herself in a conversation.
All this sounds kinda ego-crushing, but it really is the fastest way to get to a high level of speaking/listening fluency. Think about this, a language class will be populated with other people learning English, whereas a bar will be filled with chatty people. A class will have her sitting, passively absorbing a lesson with occasional practice, whereas the methods described above involve active processes. Finally, if you cease to provide an Italian-language safe zone, her brain will naturally begin to adjust. It's an uncomfortable process, but I achieved a high degree of spoken/listening fluency with both German and Turkish this way, as a native English speaker. Compared to two years of classroom Arabic, and I can hardly say my name.
Good luck. Let us know how it goes.