@pippa 

To maximize the wifi of the WPA7510 you would just do the same actions you would to maximize the router's wifi.  Change Channel or Channel width,  make sure you are on the latest firmware, and power cycle by unplugging the device and reconnecting it.  Addtionally you can try relocating the WiFi adapter to try imporve the speed.  With PLC adapters the speed is affected by interference(noise) on the powerline and how many hops (circuits) the signal has to travel between the two adapters.  this thread explains this in better detail 

Best Regards

Carl | TP-Link Support