I second the course thing - my mum has done a couple of basic computer courses through tafe - it might also be worth them seeking the local computer club locally, which tend to be filled with people who are mostly very helpful.
The guy I get my computers from is a guy in North Sydney
http://www.avo.net.au - they (for a price) can include onsite warranty stuff and would (if asked) deliver and put the machine together (at least in certain places in Sydney).
Dell deliver but don't (I think) put anything together for you (do they - never bought anything from them, and don't need help myself...)