( i might go for photography graphics designing or marine biologist
)
Some science courses require mathematics. Some offer bridging courses. Check with each of the universities you're interested in. Just head to their websites (search google).
As for your other options, you won't even need to go to university. TAFE offers these programs and if you're still keen on uni, then you can transfer and get some credit points. If you do a Diploma in Graphic Design at TAFE, you can get up to 48 credit points (1 years' worth of uni study off your 4 year program - so that's only 3 years to do at uni) at UTS and up to 36crp at UoW.
so... does your UAI scale you down if you dont choose Maths in the HSC course? O_O"
No, excluding maths does not bring your UAI down.
Choose subjects you will excel in. Interest in not good enough, as I and many others have learnt - the hard way. You may be interested in something, but interest alone is not enough motivation. If you're not good at it, and your marks reflect that, you won't be motivated at all. You'll lose all interest and hate that subject.
I'd definitely choose Photography, if I were you. Visual Arts is quite different. You can still major in Visual Communication (graphics, multimedia, etc) but the theory will drag you down if you're not into art history and criticism.
The best advice I can give you or anybody else is just to take a look at some of the past HSC papers for the subjects you want to do and see how hard/easy you think they are and what it takes to get 2 marks in one subject compared to another subject.
I regret not knowing about this before I had to choose subjects, but you HAVE TO look at these statistics so you can be realistic about achieving a band 6.
http://www.boardofstudies.nsw.edu.au/ebos/static/BDHSC_2007_12.php
Good luck!