Click on Tickets and Hospitality at the top of the home page, then Buy Match Tickets. There aren't any away tickets to buy at the moment, the Babylon has sold out and Swansea isn't on sale yet. If you want the ticket news you need to hover over Tickets and Hospitality without clicking it then you can choose Ticket and Travel News.
And when you've jumped through all those hoops, be sure to answer that survey they're emailing out about the website, it's a bloody shambles and I for one have told them so.