When at first I thought it was impossible, I picked up an Ethernet to wireless bridge (plug Ethernet cable in to it and you can browse wireless) for my desktop. After giving it a few shots, I was able to intercept my VoIP and other computers with Cain. That means I'm another step closer to finding my mystery hacker in my neighborhood. At first I was panicking, but he might just be using a wireless bridge as I am. I feel like an idiot for not thinking of this sooner. That means I was correct, he was using Cain to pick up information on a windows machine. He might just have a bridge set up.
Sorry if this isn't thread worthy but I'm certainly excited. I didn't think Cain's APR would work even with a wireless bridge, but it does, and I can prove it. Just try it yourself.
On a side note, I also got Wireshark working on my Linux machine. I never allowed it access through my firewall.......