nasa808, I've never had experience with Russian transit visas, but I am doubtful you may get one based on your itinerary. There are several daily SU flights from Rome and to New York -- there's no need in 46 hours transit. So what you're going to do is not actually transit, it's a visit.

Do not lose time with transit visas, book a hotel in Moscow, request an invitation from them and apply for a tourist visa.