Do I need a bridge? Access point? etc.

Nermal

In one corner of the house where phone line is: Netgear DG834G, acting as ADSL modem and a wireless router. Might want to attach a network printer to it in future.

In another corner - cannot easily be wired to the first - a bunch of ethernet-capable items, e.g. smart TV, satellite receiver, network storage (obviously, want all these items to talk to one another as well as to wired/wireless clients connecting to the DG834G).

What do I need to set this up?

It seems to me to be a combination of an wireless bridge to the DG834G and a 4-port switch. Do they exist?

Thanks in advance!

PogMoThoin

This set of homeplugs comes with built in wireless AP, then all you need is a switch for more ethernet ports. Homeplugs use the wiring in your electrical circuitry to connect to your existing router.
http://www.amazon.co.uk/D-Link-DHP-W307AV-PowerLine-Homeplug-Wireless/dp/B004KPLKO6/ref=sr_1_12?ie=UTF8&qid=1347200262&sr=8-12

You need to make sure this new wireless AP is set to a channel well away from the existing one, make them channels 1 and 11 so there's no chance of interference. You can give the new network the same name and encryption type and key and your devices should roam from one to the other