I am currently learning German and French, which along with my native language of English I plan to be fluent within. However, I'd kind of like to learn an Asian language since it is becoming such a beacon for industry with the likes of China, South Korea and Japan. Plus, there history and culture is so interesting compared to western nations. So, I was wondering how well can someone learn a language by themselves? I already take classes for German and French, so can't really afford any more. However, I do have Rosetta Stone classroom software access for the next two years and I probably could buy the full edition afterwards.

So buy it.

I got my French pronunciation right by watching French films and copying what the people said, how they said it. Or any film if it supports French audio. Same with games too. They have cassettes for those, but I find doing it with films so much better. It's more fun, so as a result I learned more. (I had French class at school, so I had grammar and writing all down already though, this was just for speech).

For Japanese, I guess you could watch anime, but you won't learn everything, just the basics and repeated words. Also, you may start sounding either like a squeaky little girl or a very gruff man, depending on what you watch.

Japanese and Chinese are both a lot of fun, and radically different from the languages you're learning now. They might be difficult on your own, but they're worth learning.

I'd go for Mandarin Chinese right now. It's going to be a big global language as far as business and economics goes. The sentence structure is easier to follow than Japanese IMO, but a bit more rigid. You'll want a native speaker to help you with pronunciation, because if you learn the tones wrong you're gonna have a bad time.

Learn taushiro.