My family is taking a trip from NC to Sydney in May-June 2014. Coach airfare for my wife and me will be reimbursed (budgeted at $2,250 each RT), but we are paying out of pocket for two children, aged 8 and 10. Given the long trip and our young children, I want to upgrade us to biz class for at least for the long legs to/from SYD. We don't fly frequently, but my wife and I have 350,000 US Airways points and 150,000 Delta points. Family members have also offered 60,000 US Airways points. My wife and I have separate US Airways Premier World credit cards that are adding about 10,000 points per month. Tentative departures are May 26 from NC and June 14 from SYD, but we have a little flexibility on those dates. We live close to GSO but can easily fly from CLT or RDU. What is our best strategy to upgrade to biz class?