I agree with Sara and Cat...Closure is not to be found in a confrontation with OW (can you really expect clarity/honesty/remorse from someone who obviously has some major character flaws?).
As much as you might dream about it, any contact with her will likely not contribute to moving forward in your R, and can potentially damage your current progress. I can't say I've ever closely watched any of the daytime talk shows...but do the knock-down-drag-outs between wives and other women EVER make the people involved look poised, mature and healthy?