Hauppage 2250 Media Center Kit
http://www.newegg.com/Product/Product.aspx?Item=N82E16815116036
You can operate independent on your cable box. It has 2 Digital/Analog tuner which you can use to record and watch HDTV. You can connect directly to your cable line or cable box.
You can use it on conjunction w/ your cable box. The media center kit will enable you to control your cable box feed the show to one of the 2250 video/audion inputs.
This an excellent unit. I had mine early 2008. I use it as my PVR and DVR. It works well w/ Windows Media Center. I tried it on Vista and W7.
Or you can try this HDMI capture card from Hauppage
http://www.newegg.com/Product/Product.aspx?Item=N82E16815116065
You can operate this in conjunction w/ your cable box. It capture and record HD video/audio on its HDMI inputs. It has a breakout cable for traditional component analog video (also HD capable).
Both devices media center kit will enable you to control your Cable box.
Here's hauppage webpage:
http://www.hauppage.com/site/products/prods.html
The thing that i like on these hardwares.... Your Hard Drive Space is the limit of your recording. I have recorded shows in HD up to 30Gbyte single file.... 4 hour event like the super bowl or world cup... All in HD.
I placed one 2 Terabyte drive just for my PVR/DVR space... No issues it keeps recording all the show i want it to record.