Potential agent suggestions for Melbourne actor?

Hi everyone, I have no doubt that posting a request like this here is very unprofessional of me - I'm a hopeful 18-year-old singer and actor thinking of giving professional theatre a go. I've done my fair share of amateur productions, and am planning to now start taking steps towards the professional scene. I've read a number of the great Theatre Australia guides, and so have some idea of the industry and agents. However, I'm based in Melbourne, where there are more theatrical agents than I can count. I've been to the websites of many of the Equity-listed ones, and really can't work out how to tell the reputable from the dis, and the professional from the un. I'm wondering, therefore, if any of you can recommend some good theatrical agents I could use as a starting block, to call while knowing I am getting in touch with a quality agency. If possible, I'd like them to represent performers for musical theatre firstly, and also opera and straight drama. I am also wondering if any headshot photographers can be recommended. I've been to the websites of most of the main web-searchable ones around Melbourne, and most have very artsy sites, with little more than pages and pages of photographs. Considering the price I'd be paying for professional headshots (around $300 in most cases), I'd like to feel confident that I'm going to be satisfied with the result. Thank you all very much for spoon-feeding me in my early stages :). Cheers, Will Pridmore