bummer! You will definitely want a heating core of some sort. You can usually buy them at the store, and I know some people here at CC use flower nails for that purpose.
I'm sure if you contact Wilton they will tell you how you can order just the heating core.
I tried to find one here on CC, but it said product not found...
Here's one on the wilton site:
http://www.wilton.com/store/site/product.cfm?id=3E30ACBE-475A-BAC0-505CDCE7A4EA25E5
You'll definitely need a heating core but it'll have to fit your mold. I don't know how they (the ones that come with the wonder molds) compare to the regular heating core. I have the large stand up bear mold and I think the core is smaller than the one you'd buy to use in a conventional pan. Uh, a flower nail wouldn't be useful in this case. If you aren't set on using the mold right away you ought to be able to get a replacement core pretty quickly by ordering online. Good luck, and have fun with your doll wonder mold!!
Sorry, but you really need the heating core. It's a very thin one but it screws into the bottom of the pan so it stays in place. I wouldn't try to substitute any other type of core with this pan because you are going to need the cake to be quite stable to support the doll.
Could you contact the ebay seller and see if she maybe forgot to put it back in the box after she photographed it?
It's a fun cake to make, though!
I sent a message to the seller, havent received a reply but im hoping she just hasnt checked her email and thats the case. I looked on Wilton and they are $7 plus s/h after buying the mold and if I have to buy this I will have an expensive mold lol.
I"m so happy!! I sent an email to Wilton last night telling them of my problems. I got an email today saying they are sending me one and it should arrive within 5 days. Thats good customer service. Thanks for the hep guys. Knew someone would tell me what to do... 
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