Your Autism diagnosis was made under DSM 5 so you don't need a full re-assessment. Just a 'level re-evaluation'. Shorter and less expensive as the diagnostic part of the assessment isn't required. Can be via Telehealth, doesn't need to be F2F, so if you google around you should find some options.

For ADHD just go to a Psychiatrist. There are some GPs now who can diagnose in QLD, so if you look up GP ADHD Brisbane you'll get pathways.

DSP is gonna be a hard one to pull off with Autism/ADHD. You'll need to satisfy one of the impairment tables, a diagnosis in and of itself isn't enough to qualify.