I would recommend "Pimsleur's Japanese" and "Rosette Stones" materials.
I'm studying with Pimsleur's and it helps me alot.
I also have the notes for all the 3levels in Pimsleurs Japanese 1 2 3.
put the audio tracks in your mp3/ipod and print the notes so you can study on the train/buss or on your free time at the job.
if you buy pimsluer japanese on the internet it will cost you around 800USD total.
so try find a friend and ask him/her to send you the audio tracks + notes.
I hope you can all the Hiragana and Katakana.. if not study them at
www.yesjapan.com good games to help you remember the symbols.
It will take you max 1 week :) then go on with the pimsleur japanese finish the 3 level they have then go for Rosette Stones and repeat..
if you like to have more information, mail me :)