I recently got a PS3 to stream movies from my computer in my office to the TV in my lounge. I'm trying to work out the best way to get the data there. I have cable modems in my office and my lounge.

The three options for connectivity are:
1) Put the PS3 onto the wireless network and stream data directly. The signal might be a little weak, but this should work.
2) Put another Linksys WRT54GL in as a wireless receiver, and connect the ethernet ports to the PS3 and TV. This might give better reception because of the dual antennas on the 54GL, and makes the PS3 and TV think they're on a wired connection, which apparently is a good thing with a PS3.
3) Connect a router/switch to the cable modem in my lounge, and connect the TV, PS3, and cable box to this wired connection. I'm not completely sure this will work, though I assume it's a standard IP connection so it should.

Option 3 would mean I have all wired connections which would be much faster, but I wonder if the data transmitted between my PS3 and my PC could be counted against my data allowance. If I stream a few movies a week to the PS3 that could add up to many GB a month, which would be bad.

I don't know enough about the network layer to work this out myself. Can anyone tell me if option 3 would affect my data cap, or if it the data stay internal to my house?