Wow - and I had always though DC area was expensive ! OR maybe he meant the weekly cost,, rather than initial cleaning.
Here is an Angie's List article on the subject -
http://www.angieslist.com/articles/ho...
More info also in the Home > House Cleaning link in the Browse Projets area at lower left this page.
Around here an initial cleaning for a 2000SF range house runs at least $150, more likely to 200-300 range, then about $40-100 for subsequent weekly cleanings. For 6000 SF wouldhave to be about $300-500 range initial (unless it has been routinely cleaned up to now), and probably around or pushing a $150-200 per week after that. I can't imagine doing a decent weekly job on a bathroom in less than 15 minutes and kitchen in 1/2 hour - so that is 2 hours right off the bat without windows, vacuuming, walls, doorknobs and jambs, etc - so I would guess about a 4 hour job or more weekly - probably better part of two full mandays for initial cleaning.
Search the List for House Cleaners and their reviews, and have a few come by to bid on the work.