I'm not sure what you mean by that - I assume that you want an external antenna for the router, not the USB adapter (you don't want to put the USB adapter outside!?)
Yeah - that's what I was asking - what do you mean by hooking up an antenna to your USB wireless adapter??? AFAIK, a USB wireless adapter simply plugs into a USB port on your computer, sometimes on a USB extension cable.
Antennas - again, AFAIK - hook up to your wireless router.
So...
Do you want a long USB extension cable so you can hook your Wireless USB adapter up high some where or what?