upgrade from 4s to 5s - doubts

[dimago]

Hello guys,

I need help with it.

I have an Iphone 4s Unlocked and I bought it in the US. (I am going to US next Monday and I bought an Iphone 6 with T-Mobile(Online App Store), but I think I wouldn't use it with another carrier, nobody know if it will come unlocked, right?)

Anyway, I want to upgrade my 4s to 5s. Is it possible? I need to get a new one unlocked as well. I have no hard problem, just I feel my battery going fast.

Any idea how much I need to pay for that upgrade? Can I schedule something over the Internet?

And if you have any idea about the iPhone 6 unlocked, tell me!!

Thanks!

Diego