Throw out the alfa, it sucks.
I had quite a few and never really had stable connections.
They break.
If you don't care about spending a couple bucks I suggest you go for a router board.
If you want to do something cool buy a mikrotik board.
Something like this:
http://routerboard.com/RB411LYou'll need to add a PCI wireless card yourself,.
Flash openWRT or some other open OS on it and work from there.
You can have wireless tools installed on it or whatever.
Get some Atheros based chip.