Don't worry, it's no trouble at all! I believe your Visa card should work just fine. Like Daniel wrote before, you can totally order online through our website with an overseas billing address-- Thailand or anywhere else! You are always welcome to call in to place your order if that would be easier or more convenient for you, too.
If you need any help placing your order, please don't hesitate to let me know. We're open from 9AM-10PM Eastern time, which looks to be around 11 hours behind Thailand. Or, of course, if there is anything I can do to be of further service, do let me know. I'm eager to help, and happy to do so!