I have over 150k miles (non-elite now) with continental and I'd like to use these for upgrades on the transatlantic legs of a trip to Istanbul, Turkey. The trip would be for the last 2 weeks of august or there abouts.
I've looked at various options and am only able to find an upgrade on an EWR to FRA leg of the journey. What sort of things should I be looking for apart from different dates? Is it worth hunting through all of the other star alliance carriers? Can I use my miles with them? Any suggestions would be appreciated.