@MsClean - I certainly do sympathize with you over your wire grass problem. I used to live in the Southeast part of the United States and wire grass was a problem for many folks down there.
I had a gardener come out and treat mine once a year I believe sometime around October or November when the weather cooled down and the wire grass becomes dormant.
I remember he soaked the area that was infested with the troublesome weed and then drenched it some more with a chemical, I think it was like a professional grade roundup. Your local nursery should be able to provide you with a professional strength herbicide.
Anyway once the area dried, my gardener tilled it and then laid new sod of St. Augustine grass. I was advised to keep the lawn at a height no less than three inches. The taller grass was supposed to shadow the wire grass which stunted it's growth and I eventually killed it since it no longer received direct sunlight.
I hope this helps. You might have to hire a professional gardener or landscaper like I did. I remember how persistent it is and what a pain it was to try and remove it from my flower beds every summer. Good luck to you and your lawn.