Your teacher should have some French magazines and even French books or comics for you guys to read ---> if not, they're not much of a French teacher! I would always go with reading as the best way to improve your French.
This is because you'll see all the words PRINTED on the page and spelt properly. So my advice would be to go and pick up a big dictionary ( a VERY comprehensive one) and as much reading material from your French teacher and, not in a rushed fashion, read as much as you possibly can and re-read everything. Creating a vocabulary list would be a good idea as when you are given a practice writing task you can always pull out your vocab list and use some powerful, complex sentences or expressions that you found while reading. This re-inforces the expressions in your head and by HSC exams you might have some pretty useful things to slot into your writing.
When Francophones speak there is a lot of slang and if you can't visualise the word it is very hard to learn what it means. There are spelling changes and pronunciation changes as well as slang and tenses used that you might'nt have learnt. Not to mentaion the fact that they speak FAST. So i would find it very hard ot believe that listening to French Radio is doing more for your French than reading would be. To me, knowing another language doesn't mean speaking it- we know almost anyone can do that! But actually being able to speak, read ANd write it well- that's an indication of knowing another language.
At the same time however, you can look up programmes on YouTube such as <Le Banquier> or <Le moment de verite (or au defi)>. These are the programmes i watched while i was in Quebec for 6 weeks over the Christmas holidays in 2007. (No im not some posh person who travels to improve my French instead of working hard, my mum's family lives there so we were there to visit). Watching these shows are very handy because not only is their premise already understood (and therefore not hard to grasp), but they include real people talking real French. I find that sometimes when movies are dubbed, the French is spoken faster to cover the same movement of lips as in the original soundtrack and so a lot of things are crammed. Example: My relatives, both young and old, found it very hard to understand the French dubbed version of Borat.
Right now i picked up a book from Dymocks (they're at Borders too) called 'The Ultimate French Verb Review and Practice'. This book is a real godsend and it goes through literally ALL the verbs and grammar of the French language. Even my French teacher was surprised at how comprehensive it was and she wanted to hold onto it. It is a very handy book which really allows you to absorb the grammar and verb side of French without having to worry about the meanings of certain adjectives etc.
As for speaking, all you can really do is ask your French teacher if they can possibly spend some lunchtimes with you helping you to improve your speaking or find a native French speaker in your community to help you to improve your spoken French. I found that the only true and real way to improve your French is to speak it to another French speaker, not repeat it on a cassette or speak around the house, because when you speak with a French speaker you are forced to answer questions and adjust to the speed of their voice--TRUST ME it works better!
Another tip is to look on about.com's site for French. You can find a lot of English sayings, idioms and cliches there that are translated into French. Learning just a few of them can make the difference between a pass and a fail in the writing sections as they make you appear to have a better knowledge of French than you really do. In most of the responding questions, someone always has some type of problem that only your advice can solve, so knowing how to say cliches which are pretty general (like 'every cloud has a silver lining' or 'there is always calm after the storm') in French can really go a long way!
What do i know? You'll surely ask. Well, i was pretty much at the bottom of my French class in Year 9 but after a trip to visit my family in quebec who spoke French in 2005, my attitude towards French did a 360. It wasn't that i learnt anything but i realised how important French was to me and my life. So i started to study and work and my marks steadily rose. The thing for me that did it, and continues to do so, is learning all the grammar and widely reading French. After two years of enjoying French and working slowly at my grammar and reading a bit, i now stand at the top of my French class (and had for years 10 and 11) and i got 32/35 in my listening exam this year.
PS: I'm sure you can order French boks off Ebay but i have'nt gone to those extents because after my HSC this year i will be moving to Quebec to live the rest of my life there.
I hope that all this information guides you or helps you to achieve some better results!