XBOX 360 Network problem

Okay! Let me explain my setup. Strange as it is.

Just moved into a new house that is already wired for internet. The hub is in the basement. The internet is supplied by the HOA and each connection gets its own fun loving public IP. Upstairs in the loft we setup our office and since there was only one connection, we setup the wireless router that we have and used the ethernet ports to connect both computers. We also use the wireless for our laptops which we use where ever. We would like to connect the XBOX to one of the computers on that is on the otherside of the loft router. The xbox doesn't see any computer on the network because, well, basically they are all behind the wireless router in the loft (I am assuming).

We are very short on cash having spent everything on Christmas already. Anyone have an idea of what we can do to resolve this? We need both computers in the loft online as we both work from home and so we need a hub for that. I would like to avoid using wireless to connect to the xbox because I have nearly two TBs of movies and the wireless is kinda iffy at times with some of the movies.

I am using a Netgear WNR2000v3. I don't just have a hub anymore... it was crushed/sat on.