US Airways Dividend Miles (Pre-FlightFund Merger) - domestic upgrade question

I booked a ticket on United -

outbound from SFO is on UA metal and return from PHL is on USAir metal. I dont have any status or anything on USair. Is there any way for me to upgrade the one way on US Air metal?

Thanks

Since you're Star Alliance Gold, you can purchase upgrade certificates for $40/each. They are good for 500mi each, since PHL-SFO is 2200 miles, you'd need 5. You can upgrade on the day of flight if space is available. Just ask to be put on the upgrade list when you check in. Check in online at 23:59 ahead of time (if the system will let you) to be put near the top of the queue.

See http://www.usairways.com/dividendmiles/programinfo/upgrades_mp_on_us.htm for full details.