Do you need it to be global or you "hope" it will be used globally? Honestly, if it's not a huge need right away don't worry about it.
It's like take several more months to build a site that scales before you have any users. If you have scaling or global payment issues you'll find someone to help you - it's a high class problem. Focus on getting users.
Other than that, there are also tons of conversations on the topic good to follow the topic http://members.founderdating.com/discuss/topic/Online-Payments