<<< am not sure whether to do for DSL/cable 802.11g router or the ADSL one. >>>
With Telewest broadband, you DEFINITELY want the one described as "Cable/DSL".
Don't confuse the reference to DSL with a combined "Router/ADSL Modem" which is *not* suitable for Cable broadband - it is only for use with ADSL via the phone line.
<<< I have a Webstar cable modem from telewest, the modem is plugged using the USB and not the ethernet. Do I need to buy 2 PC cards if so which ones, i.e. does it have to be compatible to the router. >>>
When you get the router, you connect the router's WAN port (Wide Area Network port) to the ethernet port on the cable modem and connect one of the laptops by ethernet cable to one of the router's LAN ports. Once it is set up, and there is very little involved for cable broadband, you need to configure the "wireless" settings. Then you can connect wirelessly to the router and remove the PC to router cable.
If the laptops are not wirelessly enabled, and you want to connect both wirelessly (you can use "wired" connections), then you need Wireless Network Adapters. These can be either PCMCIA or USB 802.11g Wireless Network Adapters. However, if your USB ports are not USB 2.0, the better option would be PCMCIA, because the data transfer speed of USB 1.1 at 12Mbps would restrict the performance of a 54Mbps 802.11g WiFi adapter.
Any 802.11g adapter should be compatible with any 802.11g router, but it makes sense to buy all of the kit from the same manufacturer to minimise the risk of connection problems. I have Telewest and I'm actually using a Buffalo 54G router with Belkin wireless adapters, and it all works well.
<<< I have contacted currys and Argos >>>
The routers in the Argos catalogue are all for ADSL, so they are not suitable.