Welcome to FT
Air France does not sell miles.
But even if they did, you could upgrade with miles only on full fare economy and it is much more money than the price you found.
For biz travel, I am afraid you should pay for it...
I dont know the rules on UA and AA for upgrading if you have (many) miles.
Regarding the fares you have found, I will consider to buy 2 round trips:
One from LAX to TXL ($614 all included, and if you want to fly on Air France, the fare is around $ 740, as on Klm and Northwest, and American airlines is around $711...)
http://matrix.itasoftware.com/cvg/di...NS-2=1&ND-10=1
The second round trip TXL-FLR ( $269 on Air France)
http://matrix.itasoftware.com/cvg/di...&NS-1=1&ND-7=1
So the cheapest fares is around $1000 for the two round trips.
In business, around $4800
http://matrix.itasoftware.com/cvg/di...4-02&Z=1&TBC=0