All of the rooms at Walt Disney World have the capacity to hold your family in one room. Even the smallest value resort rooms allow up to four guests plus a child under the age of three in a Pack 'n Play crib.
However, just because you can be in one room, that doesn't mean you should be in one room. I'm not going to sugarcoat things, if a family of five is in a value room things are going to be tight.
If
you need alternatives, you might want to investigate the Family Suites
at the All Star Music resort (call Disney reservations at 407-W-DISNEY
for more information and pricing). These rooms are meant to hold up to
six people, whereas the regular value rooms are really only meant to
hold up to four. Another benefit of the Family Suites is that they come
with a small kitchenette with a refrigerator, microwave, and toaster.
If you upgraded to the Family Suite, perhaps you could offset a bit of
the cost by eating breakfast in your room instead of out at a
restaurant.
There are also a number of other alternatives for families of five or more. You can read all about this
HERE.
Good luck with your planning.