I would definately check out a timeshare such as the Costa Linda, Playa Linda, LaCabana, etc. The CL has 2 bedroom (or 3) units that sound perfect for your size family. Having a kitchen is a blessing especially for those trying to save a few bucks! The supermarkets are wonderful in Aruba and the cabbies and bellhops are more than happy to help you with a weeks worth of groceries!

Try to rent from an owner after you decide on your resort/location. Here's the website for Costa Linda and just click on Members on the tab to the right to view their BB to see whats for rent during your time period.

http://www.costalinda-aruba.com/resort/

same for : http://www.playalinda.com/members/phpBB2/

and also www.lacabanabrc.com

Obviously there are more but those are the ones I know for sure have 2 bedrooms or more.

Good Luck!