Hey Erick, welcome to the forums. I did some searching online and it looks like an app called "Market Enabler" will do that... the catch is you need to be rooted. So that's something for you to think about...
Here's the root sub-forum for your S3 (the international version

) :
(International) Galaxy S3 - All Things Root - Android Forums
Now, this being said, I don't know if Market Enabler really works like this... this was just some Yahoo Answer post I found. Your Mileage May Vary.
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I found this app in the app announcement pages:
http://androidforums.com/application-announcements/508176-every-locale-tool-app.html
That seems like it might do what you want. It also lists a few apps that do similar things (in case *this* app isn't available in your location

).... I didn't look into this app too much, but it seems like that should do what you want.
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I was also wondering what does the last bit of your google account look like? I was thinking that *maybe* it was tied in with the top level domain... so like gmail.com instead of gmail.co.uk for example. I don't know if google uses that... but maybe..?
Anyway, hope this finds you well, and not too late. Also, hope it helps with the issue... and Welcome to android forums. We've got

epsi: in the corner.
-9to5