Hoping someone can help out. Unfortuantely, I may not be able to answer very many questions quickly, as this problem is at my in-laws and I won't actually be down there until xmas...
They have an ADSL link to a LinkSys WRT160N - this connects in the main PC and provides wireless. ADSL seems to be working fine - there are rarely connectivity problems with the PC. Wireless is a different matter - they also have a Dell laptop and this drops it's connection very regularly (on average once a day, sometimes every few minutes). Power-cycling the WRT160N seems to be the only way to resolve this - restarting the wireless adaptor and related services, even with a reboot, on the laptop does not do it.
Considering a new wireless router anyway, just because I'd like to give them a little more range. Can anyone recommend?
You should try to optimise your reception and avoid interference.
1) raise the router above furniture level
2) Experiment with channels (some will work better or worse depending on your environment)
3) If you can detect strong neighbouring wifi, use a channel 5 stops away from strongest.
4) Relocate cordless phone base or video sender etc.
5) Be prepared to move the computer (or at least turn it so your body is not between the router signal and the wireless adapter's antenna.