traveling in japan first time

Well I'm planning to go to Japan this December for while, I've found a tour that I could take dec 14-21st but most of all, I really want to go to Yokohama on the 25th at night. However I've searched all over the internet and I couldnt find any tour that could take me to Yokohama in December. A friend of mine told me though however that she found a tour on here that lasts for two days that takes you to akihabra and yokohama and that you stay in an actual japanese home with japanese parents, which really caught my eye because I would be making friends over there while I'm at it and that it'd be a great experience while I'm over at Japan. Does this place offer any such tours over here and if not, does anyone know where I can find such tours in December? By the way I'm a college student in America and this is my first time traveling over to Japan.

Akihabara and Yokohama are two different places. Akihabara is a shopping area for electronic goods in Tokyo while Yokohama is a city next to Tokio in the west. A first impression of Akihabara you can get from the sunrise morning tour: http://www.japanican.com/sunrisetours/FToursKensakuShosai.as...
but you can visit Akihabara by your own, too while you are in Tokyo.
Yokohama as part of an organized tour I do not know, but again you can visit on your own by a 30 min train ride from Tokyo. Sunrise ( and others ) offer tours in Japan with overnight stay in a ryokan, the Japanese type of accommodation.

Note also that Yokohama is ather easy to navigate on your own:
http://www.japan-guide.com/e/e2156.html
http://www.japan-guide.com/e/e2360.html

Tours of that nature are generally very very expensive. You could get yourself a free guide. check this place out
http://www.tokyofreeguide.com/ I used them once and I asked for someone who spoke Korean!! ANd they had one! Of course, I also spoke to them in English. Also check the free guide sections on this website

If you can find a guide, that's fine, but actually I would really encourage you to try to tour the places on your own. Yokohama and especially Akihabara are pretty convoluted places and I think part of the fun of exploring Akihabara and Yokohama's big Chinatown area are the fact that you come upon shops and attractions kind of by surprise. You just need to do a little bit of research such as which train station to get off at, and then from there, the bilingual signs at the train stations will point you to the right exit, there are always very good (bilingual) maps at most stations, and before you know it, you're really creating your own adventure, and I think you'll find a greater sense of worth and an experience you're more likely to remember, than if you took a tour.

It is your first time out of the states and so it's your call, but let's just say that you shouldn't be intimidated by anything, such as not speaking the language or not knowing the train system. Those can be navigated with ease, especially in and around Tokyo where many people know at least a little bit of English and are willing to help out a lost person.