My progress to level 1:
Starting from nothing (well actually a few evening classes), I went to Japan on the JET program and taught English for two years.
By the end of that I had conversational Japanese but not many Kanji.
Then I studied kanji pretty hard over the summer and went to university half-time after that. I could go straight into about third-year university level.
After that I got a scholarship to study in Japan and went back for one year (there are lots of scholarships around, the Japanese love Westerners to come over and learn about Japan). I spent a lot of that time drinking beer and reading manga, but also studying Japanese.
At the end of that year I passed level one having not done any of the other JLPT levels beforehand.
So starting from nothing it took me four years, three of them living in Japan.
Anyway I don't know if that is any use, but that is about how much it takes to get level one JLPT. (I got a good mark, about 85%
<--boasting now)
Anyway, to go on topic for a second, JLPT is all about reading and listening. You don't necessarily need a language partner if your only goal is JLPT. There are a lot of great textbooks made specifically for JLPT, but you might need someone in Japan to send you them.