[Lexy]

The book I use to learn grammar is called 'Understanding Basic Japanese Grammar' by Nishiguchi Koichi. Yeah, the title of it implies basic Japanese, but that's basic Japanese to the nihonjin. The grammar actually gets pretty advanced and along with grammar practices, it also really forces you to dust up on kanji. I just finished my fourth year of Japanese study where we constantly reviewed 'x ni naritai desu' and 'short form adjective base+ku narimashyou' and this book goes far beyond that, perhaps it will help you.