I am surprised your TV does not have an optical out. I suggest you buy a converter. They sell them on ebay for about $20. See ebay item number 330467164256. This should do it for you. The sony system as sophisticated as it is, really isn't. It is very limited with the inputs, but so is your tv with not having an optical out. My tv is like 3 years old and it has both, but my brand new dishnetwork DVR only has coaxial digital out as well, no optical! I don't get it. But whatever, this should work for you.
Also, they make these things that go both ways, so if you get one, make sure you get the one I listed above! And of course, you will need to buy a coaxial cable and a toslink optical cable.
Also, for your wii, they sell on ebay a cable that connects to your component video in connections on the back of your tv instead of the standard rca that the wii comes with. I bought one of those cables on ebay for $5 (see ebay item number 230526778487) . The video is a little better and if you use your wii a lot and your component jacks on the back of your tv are available, you should get that as well.