Without knowing when you are planning to go, I would say you could look into renting points for a 2 BR at OKW. You all would just barely fit, but you would fit. You would be looking at about $450-$600 a night. Renting 2 Ft Wilderness Cabins would be similar, around $500-$600 a night.
If having a kitchen doesn't matter to you, you could look at 3 rooms at an All Star Resort, and you'd be looking at around $350 a night. I don't know if you are on the hook for meals as well, or if meals will be every man for himself. But, you would need to do the math to know if having a kitchen and laundry is worth the $$ you'd save in meals and well, laundry. For some, the answer is yes; some, no.
I would second looking at Bonnet Creek. The accommodations I would say would really work for you, and give you lots of room. You wouldn't technically be an on-site guest, but you would be right in the thick of the action. You would be inside Disney gates.
There is also the options of Suites at Coronado Springs or Art of Animation. Price-wise, I couldn't even guess.
Just keep an eye on the Disney resort discounts and Travelocity, and you may be able to find some deals.