What the... ? Wish you had told me this last time I was at the Creek. Would have saved me about $2,500 in brake repairs Definitely bleed your brakes with brand new DOT5.1 Brake fluid (about $100 inc labour at your local brake mechanic).
I'd also highly recommend asking either a "Driving Instructor" (their are usually 2-3 at the trackdays) or someone whom has been to 2-3 trackdays before to passenger around with you for the first session (or 2). You don't need 1000's of hp to cut a quick lap... you need good lines and smooth throttle/braking. No point trying to put Schumacher out of a job on your first outing, just work on getting the lines right and learning the corners.
When the checkered flag is shown reduce your speed to about 60-80 in 4th gear (for the cool down lap) to help all your temperatures drop. When you make it back to the pits drive all the way out to the main road and back before parking in the pit garage. This will allow your brakes and engine oil etc to cool down. When you arrive back at your garage leave your handbrake off and just throw something behind a wheel. Keep your bonnet raised until your next session is due (about 40mins).
Make sure you remove anything loose from your car; Headunit, Center Console, Glove Box, sub box, spare tyre, jack etc.