Advice on setup

Need some advice on adding a wireless router to my existing setup and
wanted to make sure i was on the right track.

I have a machine with ipcop (smoothwall like app) with a USB adsl
modem. This machine has a single ethernet card which I plug into a
netgear switch.

The remainder of the machines in the network plug into the switch.

Now add one newly acquired laptop. Ive bought a Netgear WG511T 108Mbps
802.11g wireless card for the laptop and now need a wireless router to
go with it. I had my eye on the Netgear WGT624 108Mbps 802.11g Wireless
Firewall Router.

My question is can I simply plug this into my existing switch? If I
look at the requirements for the router
(http://www.netgear.com/products/details/WGT624.php) one of them is for
"Broadband (cable, DSL) Internet service and modem with Ethernet
connection". I dont have that huh... mine is USB.

Options? Id like a 100mb+ wireless network and be able to incorporate
my existing setup. Can I go ahead and buy the wgt624 and have things
singing sweetly?

Regards

Tam