re: Dollar weed .... how to kill it?

Go to Site One and get one jar of Celsius and a gallon of the surfactant. Mix one teaspoon of the Celsius to a gallon of water, and add 1 oz of the surfactant. Shake it up, and absolutely douse the dollarweed. Check on it in about 3-4 weeks, repeat. It should be turning yellow by that point. Make sure we don't have any rain within 3 or so days after you treat it. You may have to hit it another 2-3 times to get it.

That's what worked for me. Expect to have some bare spots in your yard where the dollarweed once was. You could just go buy some seed and some topsoil and get the grass to catch there, or just fertilize it.