You just need to put your mind to it. I managed to learn a years worth of German in 6 weeks. I simply went through the text book and wrote things down, tested myself etc. I found that reading German websites was good. The childrens' sections of German websites can be quite helpful as they're written in simple German.
You'll also pick up the language really quickly in Germany. I went there during the Christmas holidays. In the first week I couldn't understand all that much but after a few weeks I could understand pratically everything that was being spoken. And make sure the people over there don't speak to you in English too often. If so, you wont learn as much.
I wouldn't concentrate on grammar, concentrate on your vocab, so that you can make a sentence(even if it is all mixed up). People will understand you even if your grammar isn't perfect.
As the others have suggested, watch as many German shows on SBS as possible. Stick some paper or something over the subtitles, then you'll learn more, so so I think. "Extra German" is a really good program to watch. I think it's on at 10.30am on Mondays on the ABC. It's made for students studying German, so it's not too hard to understand. Borrow some German DVDs if you can.
And the best way to learn a language is to communicate, so if you can, talk to some other people who speak German.
Here's a site that may have some helpful material on it
http://www.germanlinx.vic.edu.au/media_links/index.htm
Viel Glueck!