Please recommend WiFi Range Extenders compatible with WNDR4500v3

the WNDR4500v3 is a N900 router. Do you plan on upgrading in the future to a better router? 

How large of an area are you trying to cover? 

What is the usage case for this? reason I ask is there are standard extenders, dual band extenders, and tri-band extenders that use a wireless backhaul for connecting back to the router. 

Alot depends on your usage goals, house size, and budget.