Well, it's a big thing to research with a lot of ins and outs. It's a point system and you buy yearly points, so basically for your party size and number of nights, you would probably need somewhere between 1000 and 1500 points, although it varies by resort, time of year, room type, etc. That many points if purchased directly through Disney would be around $175,000 to $275,000, and you put 10% down and pay the rest over 10 years, with interest rate depending on your credit, from around 10% to around 18%. But you can buy resale contracts for cheaper, again depending on resort. The yearly dues on that many points would also be in the $6000-9000 range. Your home resort where you buy your contract is where you can reserve at 11 months out, and reserve at all the others at 7 months, which makes a difference sometimes, depending on different factors like time of year, resort, room type, etc. Anyway, those are the types of numbers you would be looking at if you sit down with DVC, and you would have to ask them about financing a foreign owner, not sure about the terms on that.
With those types of numbers, you might also look at purchasing a house in the area, although I know home ownership comes with its own types of issues.