Several years ago (before) eBay, I had a piece that I felt should garner much more than I could have sold it for at a local hometown auction. I wrote letters to major auction houses back east asking if they were interested. I sent along photo's and told them what provenance I knew of the piece. Three of the 4 or 5 auction houses I wrote to were Christie's, Sotheby's, Butterfields and a couple others I can't remember. Christie's eventually email me back and was interested.
Having said that, I looked at your previous auction and believe it should sell for a lot more than the top bid you received. You can try the above. From time to time major auction houses will have movie memoribilia auctions and I would think they would be willing to place your Oscar in the auction, especially since it's pret near impossible to own a true Academy Awards Oscar.
If you want to try this route, you can look at the Antiques Roadshow web site and probably get addresses for major auction houses. I know when all was said and done we were very pleased with the outcome......good luck with Oscar
_________________
best..............T im