its not just a cable.. do you have a quality sound card with software that will record what ever into the pc without adding static to it?? i use a device from m-audio, and use live lit (software they include which will allow the recording without screwing up the signal by adding static, etc) i never did it from a tape deck to the device, but from a guitar or mic there has to be a pre-amp of some kind, such as a mixer (which is what i use). for the cable, you probably already have cables that are 1/4" jacks stereo? you can use, pluging it into probably a 1/8" to 1/4"adapter to fit the output (prefered) or headphone out will work, or you maybe need an adapter to go from 1/4" to rca which the hifi is using?
12ft away from the hifi to the computer wont kill it. its the recording equipment on the pc, using even my soundblaster card + its windows driver, with something like the windows sound recorder just addes static and distortion and the volume is not good enough either. thats why i had to get a device for it, it has a special driver for it and software to record with quality, a cheap one (less than around or about that) and an expensive one (hundreds of dollars) are about the same to my ear, the main difference is features. once you record into wavs, you can burn them to cd easily.