I don't even own a receiver or a preamp-processor. So you don't NEED a receiver.
Basically what you need is some kind of amplifier w/volume control for the speakers.
The easiest thing for just 2Ch stereo is an integrated amplifier that has audio selector and volume control so that you could hook your analog Left & Right cables.
But you might as well get a cheap < $100 5.1 receiver or just a stereo receiver.
If your TV has a built-in amp (probably 20 watts per ch

), you might try hooking your speakers to the External Speaker hook-up. If you value your speakers, you probably should not do that, however.
The receiver lets to hook up all your sources and speakers and serves as a video switcher - DVD, Wii, etc.