I have no idea. I suspect you'd need a powered external tuner, and I have no idea if these are even made. If such a thing exists, you could probably connect its output directly to the TV if the TV has a spare input. The external tuner would have to output a signal that corresponds to an available input on your TV.
Since we're talking spending money anyway, can you see if a shop can fix the TV? Might be cheaper, you never know.