Bud,
mediocre? It's not a selective school based in Sydney, which is probably why you haven't heard of it. In 2002, it was ranked 21st or something. 2003 was a bad year, with it being ranked somewhere between 30-50 off the top of my head.
For 2u english, I'll add that the school marks from 0-20, whereas in the HSC they mark from 10-20 for essays, so her mark of 80 is easily an 85-90.. there's about 10 people coming first, second and third as well, so the relative difference isn't so great. Good rank in ext. english, the top few students will be getting 48+/50, then drop down for the rest of the class, she's easily looking at a 40/50 IMO. As for 4u, I can't provide much either as the marking scheme was fucked-up since it looked at journals and shit, all of which had nothing to do with her actual story. I don't think high 30s, low 40s is so far fetched though.. I know of people who came near the bottom in previous years and got ~35.
re: German, her mark of 92 in 2u would support her rank of 1st don't you think? 3u German is fair enough, but I'm assuming a good 2u German student will still do okay in 3u German, at least get 80. They are both RAW marks.
an OKAY ranking in 2u maths? It's quite good, the top few students are getting 117+/120, she'll get 90+ no worries in the HSC. 3u is nothing to write home about, but it includes the 4u students as well, high 30s to low 40s not so far fetched when you consider her overall assessment rank is 10 places higher than her exam rank, so her moderated assessment mark will likely be 40+