Here's a whole thread on upgrading for cash on AF:
http://www.flyertalk.com/forum/air-f...s-cash-af.html
In short, keep in mind there is a W cabin between Y and J, and and by DoD it's quite possible there won't be 4 seats together or at all in the cabin you want to upgrade to.
Here's AZ
bidding program.
If you're upgrading with miles, are you trying to use Skymiles (which would typically be difficult to apply in this situation), or do you have miles available in each program?