You can check VRBO for condos and apartments but 3-bedroom units aren't all that common. Might you consider 2 hotel rooms at one of the more reasonably priced hotels? Waikiki IS where most of the rentals on Oahu are concentrated.

there just are not that many large condos in Waikiki, as Suze said. here is what came up on VRBO for 3 br in Waikiki http://www.vrbo.com/search/usa/hawaii/oahu/south-oahu/waikiki?bedrooms=3
Some would be in or close to your price range.

http://www.vrbo.com/search/usa/hawaii/oahu/south-oahu?bedrooms=3 are 3 br on the south shore, so not too far from Waikiki.

You could also look at other parts of the island like the north shore or Kailua.

Waikiki is a really fun place to be, though, so if that is your first choice, I would probably talk to your friend about sharing room with granddaughter. A 2 bedroom condo in Waikiki will be a lot easier to find, and less expensive.

The Ilikai has some huge 1200sqft two bedroom suites that also have a sofa bed in the living room area. Some of them have two bathrooms.


http://www.ilikaihotel.com/waikiki-hotel-deals/


Or, find a one bedroom suite that has a bedroom area for you and a living room with a bed for your daughter, then book a separate single room for your friend.

There are hotels in the ~$100/night range. Reason for my suggestion of perhaps getting 3 separate rooms. Which also gets you 3 bathrooms and everyone gets some privacy. Somewhere like Waikiki Sand Villa, Hawaiian King, White Sands, The Breakers, Queen Kap.