That sounds about right. Does the Fujitsu have a built in Wireless adapter? If it does, the antenna is in the lid, and a lot larger than the tiny antenna inside the Mini-USB adapter. A range of 50 feet is the norm indoors. Depending on the position of the router relative to the area where you want the wireless to work, you might add some free reflectors, or external antennas to the 2804WBR. The wireless router should be located up high, not on a desktop.
Free Reflector designs. EZ-10 is really simple.