first, you should check if you have the right driver for the usb device.

after that, you should check the Channel that you broadcast your WiFi radio. maybe changing the channel would fix the problem.

there is another issue - that involved with encrypted connection. well, that makes the connection a little slower - but you won't notice it for Web Browsing porpuse... maybe try to disable it (and make everyone around you see your passwords and url's ;))