Yes, learned the mixed kana.
Tackle katakana next. Then learn a (or a few) kanji every day. There are many resources, like Anki, to test you, books like "Remembering The Kanji" are popular too.
Hiragana is used along with kanji for native or naturalized words and grammatical elements. Katakana is used primarily for foreign words or loanwords.
Hiragana, katakana, and kanji are HEAVILY mixed in writing - so it is important to have a good grasp of hiragana and katakana (collectively referred to as 'kana') so that you can understand the structure of sentences. Then when you encounter kanji that you don't know you can look them up.
I've seen alot of people in this forum say that learning katakana is not very important - I disagree completely. Katakana is a part of the Japanese language, if you desire to learn Japanese and not just a portion of it, katakana is mandatory. Even just looking at pictures of Japan (like signs in metro areas) you see katakana everywhere. So bite the bullet and learn katakana so that you can focus on kanji and grammar. Plus, many words in katakana sound exactly like the words in English, so by learning katakana you can instantly boost your vocabulary.
For a more complete discussion of the writing systems see:
Japanese writing system - Wikipedia, the free encyclopedia .
Then start looking through Tae Kim's guide, you'll see the above writing in context, and you'll start learning grammar:
Tae Kim's Guide to Learning Japanese .
