(I wasn't sure which of these 2 posts you preferred, so I just merged them both together. It seems that lately new users aren't noticing the page that says that first posts are moderated and won't appear until approved by a moderator? I've seen a lot of double first posts in the past 2 weeks or so.)
None the less, WELCOME!

I'm pretty sure that most people will recommend that you get a textbook... something like
Genki, or
Japanese For Everyone. While it is possible to self-study, a textbook is a huge help and provides a solid structured system to move you forward in a way designed to reinforce what you've already learned etc.
TJP member Infidel has done a write-up on the pros and cons and information on many of the well known text books.
Selecting a Japanese Textbook (see also
Japanese Textbook List for some more rough draft info on more textbooks)
I personally own both the Genki and the Japanese for Everyone books... along with the Genki workbook, answer book, and audio CD for level I. I haven't made it to where I need Genki II yet.
Feel free to ask any questions you might have and we'll try our best to answer them.
TJPへようこそ!

「Welcome to TJP!」 どうぞよろしく。