Hi Eldara and welcome to Vista Forums
If the hardware manufacturer no longer supports that device, then I'm afraid that you're going to be stumped. Even if you do manage to find a driver that seems to work (unlikely), there may be issues regarding security and other operational matters. I suggest that you forget about this adapter and instead purchase another one for which drivers are available. Have a look here for some adapters: Amazon.com: usb wireless adapter
If possible, select a model that is the same make as the router that you are going to connect to.