What you're looking for is a router pair that support WDS (wireless distribution system). This allows a pair of router to simultaneously act as an infrastructure access point, and also as a transparent bridge between routers. The catch is that WDS isn't very well standardized and is therefore chipset dependent. Broadcom chipsets have this feature so you're sutck with using all Broadcom equipment.
Here's the setup for the WRT54G with Sveasoft firmware:
of the other routers that support WDS have a similar setup.
[Connect remote PC and network printer via single wireless link]
I'll assume some type of printer with an ethernet port.
You can't do this with a typical client radio. The problem is that most client wireless adapters will only bridge exactly one MAC address. You can't just put an ethernet hub or switch behind one of these and magically bridge more than one MAC address.
However, all is not lost. What you need is a "workgroup bridge" or possibly some of the "game adapter" type of ethernet wireless bridge that will bridge more than one MAC address at a time. Not all game adapters will do this so be careful. I know the WET11 will work. Linksys WRT54G with Sveasoft Alchemy firmware also has the ability to bridge multiple MAC addresses. The number of MAC addresses that can be bridged varies from 4 addresses for the 3Com workgroup bridge to 30 addresses for the WET11. I think Alchemy will do 32 MAC addresses, but I'm not sure.
The only thing you lose by this arrangement, the replace everything WDS solution, is that you cannot connect to the "workgroup bridge" adapter with a wireless client (i.e. laptop) in order to increase your coverage area by using two access points.