I´ve done more testing and come to a setup that apparently solved my wifi disconnections. And the speed issue.
I´m using a TP-LINK 1043ND V1.8 router with the new bootloader from factory and running the AA 12.09 Beta.
First i tested using the noscan option as suggested and it indeed allowed the wifi card to connect at 150Mb/s however performance testing the wifi i noticed the real speed was around 24Mb/s and sometimes as low as 2Mb/sec or 4Mb/sec.
So after this i turned back to setting noscan=0. and tryed up the wifi.
Got the "20/40 MHz operation not permitted on channel pri=10 sec=6 based on overlapping BSSes" so i tried with other channels with the same error.
I have a lot of other wifi networks near mine, i can get 10+ on my desktop wifi card at any time.
So i went back to single channel 65Mbit/Sec connection, and performance monitoring the router showed average speed of 60Mbit/sec without much variance.
So that closed my speed issues, the wifi network speed is ok now.
To help with the disconnection during load, i tried the settings bellow.
RTS THRESHOLD: 2432 (Same as my old D-link router)
FRAGMENTATION: 2346 (Same as my old D-link router)
lowered Tx power set to 10dBm (Still gives me 5 bars on signal at me desktop so its still fine).
Its working fine so far for the last 3 days, i have been playing battlefield 3 and several youtube videos and wifi seems to be solid now. Hope it helps.