I'm sorry to hear about your dilemma with iiNet djay, it sucks that you cannot use your LAN ports.
I had a look at the iiNet website as it sounded strange to me that they seem to only offer their BoB modem (which I agree is not very good anyway), I navigated to this link (http://www.iinet.net.au/fibre/what-do-i-need.html) and it says that you can provide your own modem/router as well, as long as it's capable of performing well with fibre speeds and has a VOIP port. This means that you shouldn't use a cheap router as it would buckle under the load of fibre (or even ADSL2 speeds, which is around the range you're getting), but I'm surprised that iiNet seems to not have give you this option?
When I sign up (or attempt to) to iiNet, I am going to press them that I want to provide my own router (I'll probably pick up a Fritzbox, a router that rival ISP Internode have harped on about for their FTTH/NBN connections – you can see more here: http://www.internode.on.net/products/fritzbox/), and if they refuse then I'll have no choice but to go to iPrimus (hopefully they don't have such draconian requirements). I'm in the same boat as you – paid extra for more LAN ports throughout the house, and I will be using them.