The great outdoors flying with children the other day had some info on this stuff - liek what Christy was talking about.
They said take lots of small toys wrapped up, and give them at the rate of 1 an hour. Make sure they are cheap fun things cause you might want to leave them behind on the plane.
The airline that has the air-nanny was a middle eastern one I think - not Emirates, but something like that. So not much help for you I'm afraid.
Definitly get the bulkhead seat with the basinette. Regardless of whether the little one will sleep in it or not, its still somewhere to sit tehm for a few minutes while you eat your dinner or whatever. Book that seat now.
Book a kids meal - it will come out before yours so you can feed the kids before you need to eat.
Enlist the help of the stewards etc. Tell them the moment you get on the flight you would love as much help as they can give you. Ask them for tips on keeping the kids entertained.
I found my last flight to NZ with Jenna (I was by myself, she was 9m and borderline walking) was horrible. The staff were really unhelpful, I was stuck with all the businessy type people at the front of economy (so they were glaring at me when Jenna was screaming) and I kept getting told off. Jenna wasn't allowed to lie down across seats to sleep, she wasn't allowed to crawl in the isle, they gave me terrible mushy babyfood for her. It was a nightmare!

Finally, get into your head before you go, that no matter how your children behave, no other passenger has the right to make you feel guilty. You are enjoying the experience even less than they are, so they least they can do is lay off you.
You will get through it, and hopefully it wont be too bad And besides - there is a holiday at the other end!! YAYAYAYAYAY