How to capture video from my direcrv hd receiver to my pc?

I have a ati radeon hd 5770 video card. I am wanting to possibly record some tv shows that are in hd (1080i) to my computer. Do I need software to go with my video card? Or do I need like a hd video tuner card or... any ideas!|||Definitely, the best way is to use a hd tv tuner card . such as TBS6981 PCI-E DVB-S2 Dual Tuner TV card. it is twin dual, this enables you watch one channels while record another one simultaneously. it's HD!