If she's asking for an offer of US$10,000, I would think that conversion to anything else would be her problem.
Meg, I agree with you 100%. Buyer should pay for shipping, and all related expenses. Buyer has to make the US amount available to you, conversion is their problem, not yours.
Quite honnestly, I think you should sell it on eBay. You could have a minimum bid of $6300, and a BUY IT NOW of $10000 (or a bit less if you want to be realistic...). Putting it on Ebay will help you not to have to deal with sneaky people, for one thing.
Meg, I'm sure the folks who low balled you are simply checking to see how badly you need to sell and how low you'll go, likely because they will attempt to turn a profit. There's nothing wrong with telling you to take it or leave it. If it's not enough just leave it.
I hope you get $10,000 for it. It's beautiful, unique, and probably not the kind you could get them to make anymore. It looks like a modern relic. Even if you really need the money, I wouldn't go below US$8,000