I'd say 300 for traveling back & forth (you'll need a hotel each direction, use priceline if you can)...
Do you have a hotel in Orlando?
park tickets 2 adults, 1 child 600.00
Food can be as expensive as you like, or you can do counter service for 60.00/day... need more info as to what your plans are....
We never buy souveniers, but plan $$$ for those if you want to get some....
Things that cut down on $$$ spent are bringing breakfast items for the room, water & juice for the parks & general nibbling foods!! If you want to save even more, bring a George Foreman grill for use in your bathroom or patio... you can cook hot dogs, chicken, most veggies & grilled breads... You just have to get groceries....