There is no online website where you can purchase items from the theme parks or resorts.
However, Disney merchandising can get you what you want if you know exactly what it is, and where it is sold.
CALL: Walt Disney World Merchandising -- 1-407-363-6200
Or EMAIL: email@example.com
The shipping charges can be pretty hefty, but they can tell you exactly what the total and shipping will be on the phone. No obligation to purchase.
If I had someone who was there every other month- that's the route I'd go.