No problem, I'm glad to help. I'm in the same boat as you are.
My friend last year got 99.20 and he did Commerce (majoring in finance) at UNSW. He got a WAM of 74 (which is a high credit) and he found out last week that he was accepted via internal transfer into combined law. He told me that he didn't study that much and slacked off at times. If you go to UNSW and study Commerce, with an ATAR of 98.80 (which is very good), and put in hard work you can easily get than WAM of 75+, which pretty much will get you into law.
If you look through the USyd + UNSW transfer thread here:
http://community.boredofstudies.org/showthread.php?t=253865 you'll see that a few who got 98.5ish and a GPA of 6 couldn't make it into USyd.
But in order to achieve that transfer it all depends on what you enjoy. Arts and Commerce are two completely different faculties, which one do you enjoy more? Look through the core units of both courses in the first year (at both institutions) and make an informed decision.
http://www.handbook.unsw.edu.au/undergraduate/programs/2012/3502.html
Do you enjoy accounting, microeconomics, statistics etc? If so, then Commerce at UNSW might be for you.
Also check out USyd Arts+Commerce and UNSW Arts.
I got an ATAR of 99.15, but I'm not keen on doing Commerce because I hated economics in highschool and accounting+statistics don't seem too appealling to me. I love Arts though and USyd is a better Arts degree, so that's the only reason I'm leaning towards USyd.
But for Commerce, certainly UNSW!
Good luck