Is it a limitation of public AP itself? Can you connect Android or iOS phones directly to your public AP to see what happens?

Did you turn off power saving? Maybe it helps. http://forum.tp-link.com/showthread.php?3666-how-to-solve-some-powerline-adapters-can%92t-be-waked-up-by-some-network-adapters You can also try to...

We can access video stream from NC200 using VLC. No worrries. Path: http://192.168.0.101:8080/stream/getvideo Username: admin Password: YWRtaW4=

Hardware version of your WR841N is V7? That is old... How did you test the speed? Check the download speed when downloading a file from the internet when connecting to the router and connecting...

when the rainy season home Internet connections can not be used. Is it limited by your ISP? ADSL light is still solid on? Any WAN IP address on web interface of your W8968?

If you restart the router, is your connection back to normal? What's the difference of download and upload speed when connection to the router and modem directly?