Best capture card to record xbox 360 gameplay?

I want a good capture card to post game-play videos on youtube. I have some problems though. My Vizio TV has 2 hdmi, 1 component- "via RGB adapter, 1 RF, and 1 RGB. I would get an HD PVR and use hd cables but my tv doesnt have hd av input. I have a laptop running ubuntu and the only other computer in my house is on the bottom floor (in a 3 story house) and my room is all the way upstairs. Is there a way to record it from your tv then transfer files to your computer without having to plug everything in simultaneously? Can I play my games in HD (using my hdmi cable), but record then in standard definition? The main problem is that I dont want to spend a huge mount of money and i cant stand to play my xbox on anything but HDMI (or possibly hd av cables which my tv doesnt have). Does my computer really need to be hooked up while I am playing? And is there any sort of capture card that just captures what is on the tv screen rather than hooking everything and running it through the xbox then back to the tv and to the computer? My TV also had a usb port if that could help anything and as i mentioned before it has the RGB PC input. Again, my net-book runs ubuntu linux and the only other computer (which has windows xp) is all the way downstairs. I want a capture card that cad record at least decent quality while perhaps still allowing me to play in full hd... Please Help I am clueless when it comes to capture cards as I have never used or purchased one before, but I would really appreciate someone telling me ALL my options here and the best way to deal with my technical problems. thank you in advance. :/