A "wireless" router is just a normal router but with a built-in "Wireless Access Point". You can continue to use it just as you do at the moment, via its LAN ports, but with the additional ability to connect wireless devices to it.
Wired connections via the LAN ports will run at the full speed of ethernet - 100Mbps (or 1000Mbps for a Gigabit network). Wireless connections will share the available wireless bandwidth.
Wired networking will always be a more reliable system than wireless.