Guillermo,
You need a graphic card that has a (composite ?) videoinput...... a TV-card also has a built-in TV tuner. Nice to have but slightly 'overdone'.
I'm not sure about the price.
Your posting says 'harddisk' but you did type 'mainboard'..... did'nt you ?

The Terratec DMX6fire !!
Nice try Willem ...... but I must say it works great now, since the latest driver-update. For some weird reason my system needed a few reboots after installation :
It works without any trouble..... only 1 of my friends still has a not working SPDIF (digital) input. Next week we will investigate what is causing ..... as you know I'm one of the 'troubleshooters' / 'betatesters' of Terratec.......

Roel