@SZDBLLC 

You just need to change the wires.  If you are using Cat 5 you need to swap to Cat5E or higher to get higher speeds.  Cat 5 itself is only rated for 10/100 fast ethernet 

  @SZDBLLC 

Sorry, the way i read that originally was that you were using CAT5 to your PowerLine.  I see the discrepancy.  PowerLine might work but its depends on several factors and sometimes the speeds down the Powerline are worst than if you just did WiFi.   Have you tried using the Deco on Wireless backhaul?  Transmission rates may be better then?

  @SZDBLLC 

We do have powerline adapters with Gigabit or 10/100/1000 ethernet ports so it is possible.  However, like wireless, powerline has its own barriers to overcome.  Everything that is connected to the home's powerlines creates noise, which is the same as interference with wireless.   Appliances and High draw devices like AC units and Washers and Dryers create the most.  This noise can be mitigated with the use of surge protectors.  Also the distance the signal has to travel and the quality of the lines also play a part. Lastly Powerline only works on the same circuit.  By the same circuit I mean the same main circuit.  as long as the adapters are connected to outlets powered by breakers in the same panel they should work.  but sub-panels do not.    Its worth a test but in my honest opinion if you purchase a set I would do so at a store that has a return policy incase they don't work well enough for you.