No need to apologise. My replies to your posts take days to appear on this forum possibly because I am a newbie and do not post much.
I am very pleased to see the TX-Power issue has been resolved for you. I do not, so far as I am aware, suffer from random disconnects from my AP. I am not able to test it at the moment as I lent my Ralink 3070 radio to a friend.
For your information I did find that using a Windsurfer Parabolic Reflector made a big difference to performance. See http://www.freeantennas.com/projects/template2/ The template I used is here: www.aegisarts.com/wifi/ez12.pdf
I see you apply the mac80211 fragmentation patch. Does the fragmentation attack work for you? You can test it if you have a second wifi radio:
aireplay-ng -9 -i wlan1 wlan0
see the section Attack Tests here: http://www.aircrack-ng.org/doku.php?id=injection_test