Typically you have one year from the US filing to file internationally for patent rights in other countries. You can file separately in each country or regional patent office or you can file an international patent application under the Patent Cooperation Treaty. Filing under the PCT allows you to delay for up to 30 months the expense of actually filing in the respective countries. The costs for international filings are very high, which is one reason entities typically opt for the the PCT application. The 30 month period can be used to determine whether the success of the product justifies the international filing expenses. This is obviously a very rough overview and you will want to speak with an attorney to determine the options that are available to your specific circumstances.
Time for you to hire an intellectual property attorney. This is your fifth or sixth question on this subject.
There's much truth in the adage that when starting something new "you don't know what it is that you don't know." A string of Avvo questions is not a replacement for comprehensive advice from an experienced attorney -- and, in fact, those disjointed responses can give you a false sense of security.
You can blow an awful lot of money on international protection. When thinking about international protection, you should generally focus on two things:
1) Are there countries where you will derive a significant amount of your revenue? For example, if 50% of your revenue will come from Japan, then filing a patent application in Japan may make sense to protect that revenue stream.
2) Are there countries where you expect a significant competitor to be based? Often, it is useful to be able to get an injunction to stop a competitor in their home country. For example, for computer hardware inventions a patent in Taiwan can be very useful to stop the export of infringing chips.
You can easily spend $20,000 to $50,000 in each country where you try to get a patent, so generally you want to select each country with a definite strategic purpose in mind.