Sounds like a wireless Ethernet bridge:
[wireless router]<--wireless-->[wireless Ethernet bridge]<<<--wire-->>>[pc, printer, xbox, ...]
If you want to add wireless clients at the bridge, you need a wireless repeater bridge:
[wireless router]<--wireless-->[wireless repeater bridge]<<<--wire/wireless-->>>[pc, printer, xbox, ...]
Only some routers support wireless Ethernet bridge (aka client mode), e.g., ZyXEL P-330. Any dd-wrt or tomato compatible router can also be used as either a wireless Ethernet bridge or wireless repeater bridge (e.g., ASUS WL-520GU) w/ their respective third party firmware.
Of course, standalone wireless Ethernet bridges are always available. Most (but not all) will accept a switch to their single LAN port to add more devices (e.g., Linksys WET610N). There’s also the ZyXEL WAP3205; wireless N, wireless Ethernet bridge, wireless repeater bridge, WDS bridge, two LAN ports (add a switch for more ports).