Set up on a HD tv i just bought

Ok I have a question. Just the other day I bought a TV/Monitor to replace my old TV/Monitor. It was the Olevia 332H. The TV itself does not have the PIP/Split Screen option and I just found that out after 3 days of already placing my order.

My main plan was to either split screen my cpu and my TV or just have the small box in the corner for my TV. Now is there anything I can do to have that function on my computer? Like…say hooking up my comcast cable box into my computer, and displaying whatever channel is playing on my TV, thus giving the PIP effect? Any help would be appreciated. I dont want to sell my TV on craigs!! =( thanks!