Want to buy an iPhone but have a dilema ...

I currently have a family plan with AT&T with two phones. My wife's phone is due for an upgrade and mine is not due for another 13 months. Both phones are in my name. Can I upgrade to an iPhone using my wife's upgrade option and get myself an iPhone and she just keep her current phone as she is very content with her phone? An AT&T person told me I could, and they would make a some kind of a "switch", and would need my wife's phone at the store in order to do it. Then I could walk out the door with an iPhone and she could keep her phone and we both could keep our same numbers.
I would like to do this at an Apple Store in order to utilize a $100.00 Apple gift card, however, an Apple employee at my local Apple store said they could not make this switch and I would have to buy my phone through AT&T since AT&T says they can make this "switch". Any ideas out there for me to still utilize my Apple gift certificate? Can I buy the phone from Apple and then go to my AT&T store and then make this "switch" ? I am sorry this sounds so confusing.

If it's like o2 in the UK you will need a new sim for the iphone.

The only problem i can see is that it will have your wife's number and not yours.

Thank you kindly for your reply. Yes, the AT&T guy did say in the switch over I would need a new sim card, but also said if I had my wife's phone there at the time we would both be able to keep our same number. Maybe because both phones are in my name. It sounded a little too technical for me to completely understand, but he sounded very competent.

If you can keep your own numbers then go for it.

You won't be disappointed but the wife may take it off you when she sees it.