Question about a/v cables

Ok, i don't don't know much about cabling so if someone could help me out without too much scorn I'd appreciate it. 
 
 I just bought a new 5.1 reciever, and am running the cable now for my PS2 and Wii.  The problem is that there aren't enough a/v outs to the tv.  The dvr input has a/v in with only a single video out.  So my question is this: Can I take a regular red or white cable and run that as the video cable to the tv?  I'd hate to have to pay 5 buck to just get a yellow video cable off the internet.  
 
On my old receiver I had a switch box with buttons that you had to push to switch the inputs, but really don't want to do this again as getting off the couch to switch between Wii/PS2 defeats the purpose of being a lazy American. 
 
Edit: Not at home atm, otherwise I would have just tested this out already.  So I'm asking here otherwise it'll eat at me all day at work whether this is a fix or not.