Damn sorry man, I usually have an answer for most things but not having a network to be on is more of a money issue than anything but if your looking for a cheap way out without losing your shirt a friend of mine has one of those 4G dongles you plug into your computer via USB, he uses it for his PS3 to be on line but you need to have unlimited to use it really. The PS3 wasn't designed to send large amounts of data but instead uses what's called "Packet Data" unless your actually on video chat the amount of data is really small even on the larger games as each user only sends and receives data in small packets the disk or drive based games handle the response info as it happens.
The XBox works the same way but the data incorporates direct link options (subnet) for game chat where the audio and low res video is shared if applied. I haven't looked into XBox though as I'm more of a Sony guy when it comes to those things but where there is a will there's a way, you might wanna look into changing the firmware on an old router or configuring it to use a network that is too far for cell wifi but not so far that another router can connect to it so you would be using it as a bridge. Something to think about.
