wireless USB adapter range?

[FreshFish]

I am curious what the range on a cheapo USB adapter would be. My girlfriend's house has a wireless network that she wants to connect to from downstairs (the router is upstairs). I am a total wireless n00b so I want to be sure that if I buy her a $20 usb adapter (or PCI, whichever gets the better signal...I figure USB because its not internal) that it can get a decent signal. This is a temp. thing, so I don't want to spend a lot.

THanks

 

[n0cmonkey]

I get good signal with PCI ones. I haven't tested my USB ones too much. I get good signal with this adapter, through a floor.