Average childminder rate is 6.37 an hour, for two children that's 12.74. Original suggestion was 4 hours a day, 3/4 days a week (let.s say 3.5). Fro six weeks that's 1,070 for the 6 weeks. Later OP said WORKzilla was asking for 7 am - 2 pm, that's 7 hours a day and would be 1,873.
That's just assuming average childminder rates, consistent requirements and no discount for second child. No idea if that's reasonable.