Most routers today are actually Router+4or5 port switch, this allows 4-5 ethernet cable connections to computers in your house plus up to 250 wifi connections.
The intergrated switch in the router allows you to create a real network for 4-5 Cat5(e) devices (ie computers) plus wifi connections, you can also add another hub or switch to the router to get even more connections if needed, most homes only need 2-3 ports. But this setup gives a "real" network, in the router you can choose (within limitations of the router) your WAN IP (ie - 192.168.1.1) plus subnet, etc.
The point of getting the router is to avoid using Windows internet sharing, the ICS of windows is ok in certain cases but it has to many negatives for me. You can still use ICS on top of the router but it doesn't make too much sense incept in rare cases.
The USB might be a problem, most routers are DSL or Cable connections as inputs and Ethernet as output, there might exist a USB router but i don't know of any. ethernet is the standard for newtorks not USB.
The range is ok for most normal houses, depending on which router you choose a lot of companies have accessories to extend the range if necessary. they are very reliable if you get one that works for you, many people have written that they have had problems setting them up, for me it has always been fairly easy.
To give you my example;
I have a DSL connection which connects to a Linksys wrt54gs (router#1 - router & 4 port switch & wifi), from that router one port goes to another wrt54gs (router#2 - set as wifi access point) which is acting as a wifi access point because even though i live in an apartment the wifi signal is very weak from one side to the other, this allows me to sit outside on the balcony with the laptop and have my wifi connection to router#2, the other port on router#1 goes to a smc8508 which is a 8 port gigabit switch. There are 5 computer plugged into that switch (all ethernet), there are 2 laptops which can be either plugged into that switch, use the wifi connection of either router or be plugged into router#2. Ultimately the network can support 7 connections on the SMC8508 (this is the gigabit (1000Mbs) part of my network - 3 of the 5 computers have gigabit NICs) plus 3 connections on router#1 (these are Fast Ethernet ports (100Mbs)) plus 4 connections on router#2(again these are 100Mbs ports). The wrt54gs also supports 254 wifi connections which i have the 2 laptops, a wifi printserver, and an electronic organizer which has an integrated wifi connector.
Granted this is a bit more than most normal hoseholds would need but to give you an idea of what is possible.