Hi Emma,
I would recommend that you take a look at the
Rooms for 5 Guests or More section of the Walt Disney World website.
You would be really be looking at a two bedroom villa at one of the eight Deluxe Villa Resort Hotels which sleep up to eight Guests or the Treehouse Villas at
Disney's Saratoga Springs Resort hotel which sleep up to nine Guests. (You can see a description of these rooms by clicking on the Room Types & Pricing tab on the attached link)
If you are for budget friendly options, I would suggest that you price up two standard rooms at a Disney Value Resort which would give you the added bonus of having two bathrooms at your disposal. (If you decide to go for this option, remember to request ajoining rooms)
There are some great offers available to UK Guests covering the dates of your trip from the
Walt Disney Travel Company for 2013 holiday packages which include FREE dining during your stay, $200 to spend at Walt Disney World and a 14 day Disney ticket for the price of 7. I would highly recommend that you check those out.
Wishing you a magical holiday filled with memories which will last a lifetime!