I will also take a look at Nihongo Master. Thanks for posting the suggestions.
grandta14: I am a complete beginner at Japanese, and I really suggest you start with some sort of textbook rather than manga/games. Having said that, if you can support your language studies by immersing yourself in something that interests you, such as manga/games, then I think you should do that. In fact, that's something I'm doing. But until you have the grammar, the kana, and a reasonable vocabulary down your time would simply be wasted on manga/games.
As to managing your limited time, here's my advice. I've started Japanese and have previously studied Latin and Greek and attempted Japanese. Unless you engage with the language a little bit at least every day or almost every day, you won't proceed past the basics. It can be hard to find the time (for example, I'm pursuing Japanese alongside my doctoral thesis and my study of philosophy generally). But learning a language demands that sort of effort.
Another suggestion: Someone on this forum posted a video of a lady talking about learning languages. She argues that you should listen to music and radio in the language you are trying to learn, because music coupled with lyrics engages more of the brain than mere recitation of words, and improves one's capacity to retain information and embrace a new language. So listen to Japanese music. I'm doing it, and it is helping, even if I can't understand all the words. In particular, I am increasingly more comfortable speaking the words and following the audible character of the language.
Another thought actually - in your spare time, browse the threads in the beginners section of this forum. I've found answers to some interesting questions there.
I hope this helps.