This could potentially be worth tens of thousands of dollars. Only one thing is for sure - absolutely do not sell this without having it professionally appraised first. Your best bet for a sale would be an auction, and I'm not talking eBay. Take it (or send it) to Christie's. They will appraise it, and list it in an auction that contains other similar products. The brochure they put out will have your item in it, so the collecting community will be well aware of the sale. Yes, you will pay a percentage, but they will get it sold for top dollar. This is the only way I would consider selling something as unique as what you have.
Before Christie's will accept it you may need to have it authenticated. This will require a professional service, and I am ignorant in this department. I am sure a google search for babe ruth authentication or signature authentication would yield results.