For starters, you don't need to go out there and prove how awesome you are. Take it easy and learn your car first before trying to get a lap time that'll make peoples jaws drop. Work up to that point, don't start there.
A decent street tyre is adequate to learn your car. They are nice and progressive and give you a heap of feedback as to when they will let go. Scrub out, squealing, screeching, etc Some will tell you to go for RE55 straight from the get go. But semi comps are a very different tyre in comparison to the streets you're probably used to. Streets will add a few seconds to your times, but again work up to it.
A fire extinguisher is a necessity. This will need to be solid mounted to the car. Best choice for fitting is the lower rear seat bolts. Make sure it has a metal bracket and that you don't tech screw it to the floor.
THe blue triangle is easy. Head down to your local Jaycar, Autobarn, Dick Smith, etc and pick up some blue electrical tape. The triangle needs to be 100 x 100 x 100mm.
Bonnet restraint is also a nice 15 minute job. Head down to bunnings and pick yourself up some plastic coated decking wire. You'll need about 60mm. Cut it in half, get hold of some of the wire straps to suit. Loop it around your radiator support panel and one of the holes in the bonnet bracing. Get yourself a loop clip and it's sorted and only cost you about 30 bucks.
THe other thing to get onto before you venture out, is maintenance. Most scrutineers will not look favorably on a car that has oil leaks, dripping coolant, etc. So clean that shit up. While you're at it, doing a fluid and filter change.
Get yourself an ADR approved helmet. They are not cheap. $150 will get you a new helmet. Don't get an ebay helmet. Cheap, but mostly out of Taiwan. No approval stickers, means you cant run with your nice looking helmet that cost you $35 delivered.
Other than that, get out there and have fun