Okay that's quite a lot then. Shame it didn't go through, but maybe that'll happen sooner or later when the majority becomes more vocal so the politicians realise that their follow actually do support it.
Unfortunately I'm not confident. Gay marriage may be a big issue, but it's not the
biggest issue in Australian politics right now. Elections at the moment are largely decided in bogan parts of western Sydney and Queensland. They hate taxes and they've been convinced that the current government's price on carbon is a tax
when it's no more a tax than parking fines are a tax on driving. They want more middle class welfare ("zomg we've pulled little Jimmy out of the state-run school and put him in a private school and now there are fees?!?!? We want the government to pay for that too!!!!1!!11"). They're xenophobic, so the rather benign matter of asylum seekers has been whipped up into a racist fervour that poisons any and all political discourse that comes into contact with it. And these are also the places where you're most likely to find homophobic types.
The current state of play with the major parties is:
Labour (centre-left): Currently in power, has adopted gay marriage as party policy but members of parliament are permitted a conscience vote rather than having to follow party lines. Some right-wing unions are quite powerful within Labour and their leadership is socially conservative, hence the failure for more than half the party's members to vote for gay marriage. Labour's historically been based around the working class and had an emphasis on class conflict; it is struggling to adjust to modern progressive politics and the reality that almost everybody in Australia now sees themselves as middle class.
Liberal (centre-right): Will almost certainly win the September election. Party policy at the moment opposes gay marriage. Due to the nature of Aussie politics, the Libs will almost certainly be in power for the next six years if they win, and probably nine. However, some prominent members
do support gay marriage and the party might revise its policy to permit members a conscience vote in the next few years. The combined vote of socially liberal Liberal and Labour politicians alongside the Greens might be enough to get gay marriage over the line, but I don't see this scenario happening until at least 2016-17.
Nationals (centre-right agrarian): Minor partner of the Liberals in coalition. Represent rural constituencies that are socially conservative. Definitely won't support gay marriage.
Greens (left): The only major party at the moment that is actually committed to supporting gay marriage.
It's depressing! Right now the best hope is that individual states will pass gay marriage laws and then seeing how the High Court interprets the constitution (since it's debatable whether states can legislate for gay marriage or not). It's likely that a gay marriage bill will pass in at least one state this year.