Ok ok, as I expected, I was wrong in the following points at least.

• This green beam has not passed ETM, so we should omit one 0.06.
• Altough I wrote 1-exp(-2 (r/w)^2), what I calculate was 1-exp(-2 (r/w)).
• r should not be 10 mm but 5mm!

Taking these all,

• 10mW * 0.0787* 0.06* 0.9^5 = 28 uW

Ok, maybe the next round would be to check the measurement...