Dave,
Here's how I would spend your money.
A 2x barlow is pretty well essential.
Andrew's usually throws in a set of colour filters as well as a Moon Filter. So to get full use of your moon filter, you'll need a set of "Moon Phase Maps" . You can order them from
www.astrovisuals.com.au.
An O111 or UHC filter would be nice, but you can get along without it for a little while.
A shower cap. You can buy them in packs of 4 for about $2. You'll need one to cover the mirror end of your scope. Otherwise you'll have spiders moving into your scope, then the frogs will move in to eat the spiders.
A sheet of solar film. Then you can use your scope day and night. An A4 sheet costs about $40. You'll only need half that size, and I'll buy the other half off you next time you're at Rons.
A red light torch, a log book, a copy of Astronomy 2007.
A card table to put all your stuff on.
A water proof cover for your scope.
A tarp to set up your scope on, in case you drop an EP, you don't want it falling in the dirt.
8 Rechargable AA batteries with charger. For your battery eating cooling fan.
That's all I can think of for now.
Oh yes,
Red celephane, sticky tape, cable ties, plumbers tape, lengths of elastic or velcro to stick and hold things together and in place.
Scissors to cut the above.
Small tool kit, both types of screw drivers and a small spanner.
Lens Pen to clean EP's
Old towels to wipe the dew off your scope before packing it away.
A sturdy plastic case to pack your EP's into.