make sure there is no radio interference from things like 2.4GHz phones, microwaves, anything else that uses 2.4GHz frequency. You might also want to look at the power settings on the card. Intel cards have a setting that can lower the power so it saves power life and lowers signal(this is what centrino is really all about). You might also want to tinker with the antenna position on the router, try different positions and see if it makes a difference. Also check the antennas on the card if it is an internal in a laptop(you'll likely need to pop open a door and check the connection of the antenna wires on the card). If you still need a boost, you can purchase aftermarket high gain antennas, range extenders and other devices that can help boost the signal so it reaches further.