How to change country in App store

I've been fighting with this issue for over several days so I'd appreciate if someone could help me out here.

So I got my new iPad mini about a week ago. While registering it with the iTunes (or maybe App Store, I'm kinda drawing a blank here) it asked me to specify a country. My family originally is from Germany and I speak German, so just for the heck of it, I thought, what if I specify Germany? So I did. Everything installed OK, but then the time came for me to set up the app store to install some apps. And that's when I hit a brick wall.

When I go to App store a popup comes up telling me that some information needs to be entered. I click OK. It then brings me to a window where I'm supposed to specify my payment information -- credit card and such. So I do that. Mind you that I live in US and I specify my US visa card with my US address. When I click Next it tells me that I cannot use this card for this store. It drove me nuts! I even called my bank thinking that my credit card got hacked... they said it's in good standing.

Then if I log out and log back in, the app store has this option "View Apple ID", which I use and then it shows, Country/ Region -- Germany. I click it and it says, "Change country or region". I click it again. Then it says Store - Germany. I click it again and pick United States. Click next. Then confirm EULA, click Next. Now everything looks in English (before it was in German) and I select Visa and type my visa number and then my address and click Next. After which the spinner comes on and after a second or two I get this window (attached) that says,

"Your session has timed out. Please try again. Code: 5107"

I've been trying again since last week. How long am I supposed to keep trying to start using my new iPad????

PS. I am at a point of bringing it back to a store.... seriously!