New PC with existing wireless connection!

Im building a new PC but I'm planning to keep the current wireless connection setup, because I don't understand much about it. However, I just found out that my current wireless USB adapter will not work with Windows Vista 64-bit, even with updates. Vista 32-bit is not an option for me.

So what I need to do is buy a new adapter. But what about the other components? I don't know their purpose exactly, because I got them when the entire apartment complex got a high speed connection. There are two devices next to my landline connection, and I have basically no idea what they do The other one is a router of somekind, that much I know.

Now, if I buy a new USB adapter, do I need to buy two new devices to replace those that are currently sitting there next to the landline connection? Or can I just buy an adapter for my PC and let it connect to those old devices?

Please help!