Where on earth do you live... and how much is your internet costing you.... it must be a fortune!!
one important thing to consider first, is your connection always on, or do you have to tell the computer to connect before you can use it?
if it is always on then any cable router will do the job just fine, if you have to tell the computer to connect to the internet it gets a little more complicated as you will need a router that can tell the modem to connect instead of the computer doing it.