Depending on the time of year you go, the 3 bedroom Grand Villa (only available through DVC points), is (very) roughly $1200/night - more in high season, slightly less in off seasons. You can look at DVC point calculators on any rental agency website to see how many points are needed per night, depending on the season, and if it is weekday or weekend. Then calculate the number of points by $13 (somewhat standard rate through agencies for buying points, can possibly get slightly less buying privately with an owner, but right now the GCH villas are so popular owners are starting to charge more than $13 per point).
A GCH 3 bedroom suite (not part of the DVC villa section), which does not have a kitchen (just mini fridge and wet bar), and can be booked directly with Disney, was quoted to me today as about $14,000/week for a May reservation. A 2 bedroom around $10,000, 1 bedroom was $8000.
I am not a DVC member, and I am currently trying to figure out a way to get the Grand Villa for a week next May which is why I have researched all of this. After talking to several owners, and a couple rental agencies, I was pretty much told it is almost impossible due to the number of points needed for a lengthy stay (more than a couple nights).

So if anyone here has any inside tips for me on how to get the grand villa for at least 5 nights, it
would be greatly appreciated!