I have a phone modem DSL in my office that is 600 feet away from my front room and I found out that you cannot add another modem to the same line...Some one suggested that I get one of those plug in to the wall units tha use the electrical system... but I dont have a computer in there, but would like to be able to use wireless devices trough out the house. can you put a D-links or something like that to brodcast wireless signal?