Sorry, wasn't sure what info was needed. Yes, our home is concrete. The desktop will be connected via DSL modem. The laptop will be used throughout the house and outside. Largest distance from the router would be about 60 to 70 feet.
Your laptop should already have a wifi card installed so you will only need the router. The hotel I stay at in SD uses the same router I have, type G. The building is concrete and with the office door closed and the door closed to my room I have no problem getting a signal. Actually I can pick up a signal on the rooftop terrace (5th floor).
Maybe someone more in the know will chime in but I feel you will be fine with the LinkSys 54G. At home my router is in the basement and in my 2nd floor bedroom I have never had a problem getting a signal.
When setting up the laptop it is a lot easier if you have a usb flash drive to transfer the security data, if not you can enter the info with the keyboard.
Trust me, it is really easy to get a wirless system up and running.