Try different channels. Besides, try channel width 20MHz.

Probably, wireless card built in your laptop is working at 150Mbps. If it is also 300Mbps, on 4300 page, change channel width to 40GHz and secure your network as WPA-PSK, AES.

You can install powerline scan on your Windows PC, press connect to log into webpage of TL-WPA281, and go to wireless/wireless settings to fix a channel to ensure a more stable connection.

I think you can post your configuration screenshot about port forwarding on your W8968. But if you are configuring FTP server for USB storage devices on it, there is a detailed instruction....

I think you need to open port 3389 for your home PC on TD-W8968. Log into its web-based utility, go to NAT---Virtual Servers and add new. You'd better assign a static IP for your home PC.

If your daugher's room is in the same electric meter as well, I think TL-WPA281 is a good choice in your situation. You can pair your existed PLC device and WPA281. And then, when you plug WPA281 in...