Grrrr....why does everybody ignore RMIT? I know you said your parents would be upset if you don't get into Monash or Melbourne but RMIT is terrific. I had the choice. And I chose RMIT. Even if it has lower scores. The course is terrific, so are the facilities. I have only completed first year but already I got offered civil engineering vacation work. At work all the people in the highest position are RMIT grads. And my bosses say they love RMIT engineering grads.
I don't work for RMIT. But maybe explain to ur parents that for engineering (no idea about commerce - although the MBA (i guess it would reflect on all of commerce) at Deakin is ranked best in Australia) there are lower-entry, and (IMO) better courses than those at Melb/Monash.
As for feeling bad - I guess you could just have peanut butter sandwiches everyday like I did. All you have to do is buy a loaf of bread every do often. Thats cuts down on $35.
Also, I agree with ninwa (NOTE THIS IS NOT A PERSONAL PLUG - I DON'T EVEN TUTOR ANY OF YOUR SUBJECTS (except methods but if you are gettin that for free, don't change now)). There are plenty of good tutors out there that are much cheaper. But stick with what is working for you. If you go well on the first set of SACS, keep the tutors. Do some external tests to test yourself. If its working, don't rock the boat. But if you find you're getting charged $70ph for accounting and you get C+ on the first SAC - it's time to look for someone else.
Patience my friend. Just remember, your parents only have to do this for one more year. There are plenty more years after that for them to lounge around whilst you work your ass off establishing yourself as an engineer.