Answer: All of your stated options are valid approaches depending on how quick a fix you want and how you feel about using herbicides. Your options are basically to improve the turf gradually through some replugging and lots of proper lawn care (regular mowing, watering and fertilizing). Most weeds can be overcome by the vigorous, healthy turf.
The other option is to wait until about April, kill the weeds and turf with a herbicide like Roundup or Finale, and then resod or plug in new turf. You may want to do a soil test and mix in some needed nutrients with some topsoil prior to resoding. Your County Extension Office can assist you with soil testing as well as advice on herbicide application and turfgrass selection.
Thanks for the question!
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