You can't, period. You will always need some kind of tower or CPU in order to convert your TV into a computer. This is because you need a processor and various other circuits in order for a computer to function (they have 4 basic functions: fetch, writeback, decode, execute). Essentially, your TV is just a monitor; you can't even watch TV without having some sort of antenna or cable box.
technically, in our country we have a device that's called Surf TV. when you connect it to the TV, you can surf the net (you have to have a keyboard as well though). i havent tried it (and have no plans to do so) but here's a review: http://funadvice.com/r/3jucapcfpr
oh, btw it doesnt have storage and no MS Office capabilities but maybe you can use online word processors and stuff like that.