AV PreAmp vs. AV Receiver

I would like to be able to easily switch from VCR to DVD to DVD/CD use in an inexpensive 2 channel system by/for the TV. I have a cheap (in place) Onkyo two channel receiver and another integrated amp that can be considered for use. None are "AV" designed. Would I do best to get a cheap new "AV" receiver, or would the addition of an "AV" preamp give me the best performance, (within the same price range?) This is not for critical listening, just for TV/movie sound and background music. Will be pumped through some PSB 300i speakers. May add a sub later. Thanks for your help. Charlie
Charlie- You didn't mention what cheap is to you but in my experience AV preamp are generally higher end products and would be more expensive. I even had a heck of a time finding an AV integrated. NAD makes them at fairly low price point (think I paid about $350 new for a prologic unit). A sub will really improve your enjoyment of movies and you'll need rears for surround. A prologic unit would be pretty cheap now, but DD is definately worth the extra $. You will definately want a center channel speaker.
You will need to spend at least 500-600 for a used pre/pro (Sherwood Newcastle 9080 abd Sony 9000 spring to mind), but if the rec and int do not have pre-out/main-in connections, you can't use their amps. You're probably better served with a receiver. There are a bunch of good new and used ones out there depending on your tastes and price range. Can you give some more detail? Budget, composite/S/component video, intent to move toward full HT, etc?
Thanks for the advice, gentleman. In this situation, the room and furniture do not allow for surround sound speaker set up. I am really looking to be able to use a DVD player both for movies and cd in a system that gets very little use. I was mostly concerned with the signal loss/contamination associated with the switches in these components and was looking for any "red flags" from experiences out there, (i.e. are the $350 receivers so bad that they are not worth the convenience.) Thanks again for your time. Charlie