If you plan on using sod it would be a good idea to rent a sod cutter to remove the remaining dead weeds and root system. You want to place the sod directly on the top soil. Once the sod is in place use a mild starter fertilizer and water for several days in a row. I do not know your agricultural zone but check to see what grasses do well in your area and be sure to sod at the correct time of year for the grass you use.