You can't route the video out from the TV to the laptop, but you may be able to get a card that will enable your laptop to act as a TV. Do a search for Laptop TV Tuner Card.
If you have a monitor with HDMI or S-Video IN you can use those with your TV box as well. I did that for a bit when our TV broke.
You can always use Hulu or Netflix to watch as well. Netflix for $10 a month offers tons of TV shows, just not the ones on this week. Tons of TV shows have almost all of their seasons on watch it now so you can stream it to your laptop.