Harry,
other people on this group are much more expert on this issue than myself. I have found the usb wifi adapters such as the Gigafast WF741-UIC Wireless Adapter. Most of these similar products seem to use the ZyDAS chipset Very good reception and very easy to set up. I have not found as good performance with the Linksys WUSB11 USB adapter model. to boost reception check out :
Harry wrote: