Wow! I'm very surprised to hear that most schools don't leave work for you. I work an hour north of Sydney and pretty much every teacher at my school would leave work for their casual teacher, expecially if they knew in advance (ie going to a course, or having a planning day at school) The form we leave for the casuals also tells them about any special needs in the classroom, and the duty they are required to do. The assistant principal actually praised our staff as even if we call in sick in the morning, most teachers would email their grade partner who would then pass on the work to the casual teacher, and she said we aren't actually expected to do that. Do you find that grade partners are helpful? I know that I always help other casual teachers out that are next door to me, and they should at the very least have a copy of the program that you could have a look at.
Sounds like you are doing a great job though
and grammar lessons are a great idea!
I guess I always like to leave work for my casual, as I know I would want the same if I was in their position. Hope you are enjoying Austalia though, hope you didn't move here to experience our summer....has been a very cool summer (which I love, as I am not a fan of the heat!)