Newbie advice please

Hi
I got a PC upstairs with a Linksys PCI Wireless card and a laptop downstairs
hardwired into a wireless -g access point. I'm currently online using a
PCMCIA ISDN card via the laptop which also allows the PC upstairs access to
the internet.
I looking to upgrade to Adsl but would now like to be able to use the laptop
anywhere in the house without having to hardwire into the wireless access
point which limits my use of the laptop to one room.

Here's what I would like to know..
Has the (BT)Adsl modem to be phyically connected to a PC ?
or
Can I hook a Broadband router to the Adsl modem and hook the router to the
wireless access point and get a PCMCIA wireless card for the laptop thus
giving me no wires to the laptop and the upstairs PC.

If the Adsl modem has to phyically hooked up to the PC is there anyway I can
have the laptop and the PC upstairs totally wireless.

TIA

George