I'm guessing your going to record a Machinima or somthing. I own a capture card... Took me 3 months and costed me 120 dollars for it and it doesn't even record in HD! You can find some capture cards online for like 50 dollars but you have to physically put the hardware device in your computer for most of them(Like this)
Cost Online: 105
The big problem with that too is; you have to know what your doing or else its pointless.
OR you can search for a capture card like mine (which looked something like this)
Cost Online:15........Cost In store: 75
Which plugs in via USB.
Ether way; you will be lucky to find one in stores and find a HD capture card.