Is this iPhone considered an upgrade?

Okay, so I'm on a contract with at&t. About two years ago, I wanted to upgrade to a smartphone. Well, the IDIOT salesperson convinced me to buy a 2 GB Samsung double time. I hate it with a passion. I want to upgrade, but I can't until October. My dad told me for my birthday, that I could buy a iPhone 4s off of ebay. He has buys and sells off of ebay frequently and has had no problems, so I jumped at the opportunity. What I want to know is this: If I bring my own unlocked phone to At&t, will it be considered as an upgrade? And if it's not, than I can upgrade to a 5 (or the newest) in October?

No it's not considered an upgrade. Upgrade means you renew your contract to receive another phone for free (depends on what you want) from your carrier directly. You can add as many different phones you want to your account and your account remains unchanged. So if you get a new phone now, activate it, you are still qualified for an upgrade in October, with a new contract of course