Im back in the office now so I can give you more details of the text books that i use to teach IT
Computer Desktop Encyclopedia 9th edition
over 15000 terms and a cd with another 5000 on it
VCE information Technology
Enterprise Skills by software publications
Computer Fundamentals by Software Publications
System Maintenance by Software Publications
MCSE training kit "Network Essentials Plus" by Microsoft
The fundamentals of System Administration by John Hamilton and Daniel Smith
There are more that I listed previously.
A good idea is to go to the Boards website and download the part b of the syllabus if your teacher hasn't already given it to u. On each of the competencies there are HSC terms and knowledge that you need to know to sit for the HSC (the last column in the info) research these terms and rote learn these. You will notice that someone last year summarised these and posted them on this website.
You must complete the core topics and 4 of the electives. The cores will be the ones that you will be examined on.