First off, nice AV receiver BTW.
I don't have this particular model, but I downloaded and familiarized myself with the user guide for yours. Your Marantz does not have built-in wireless capability, but it does for wired networking.
If your goal is to have it connect to the Internet by a wireless connection, then you have a few options to explore: 1) Although the SR-7007 has a USB port, I don't believe that it would support connecting a USB wireless adapter to. You may want to check with Marantz support to verify this, 2) Use an 802.11n AirPort Express Base Station (AXn) as a wireless Ethernet bridge. This option would require a second wireless router to provide a wireless network, and 3) Connect the Marantz directly to an existing router by Ethernet