Green Card

So I'm Nigerian, but I reside in the UK at the moment on a 4th year HSMP visa (2005). The wife is American. I have once applied for a US visitor's visa, but got turned down on the grounds that I was (back then) engaged to a US citizen, so my ties to her are stronger than my ties to the UK.

My problem - my wife wants to move back to the US. We currently have two children, and it's quite trying for her to watch over them on her own. Her salary at work is less than what it would cost to pay for childcare for two kids every month, so that option doesn't exist for now. So I applied for a green card so that I could go and visit and spend time with my family when they moved back.

I have done my final interview for the green card, and have been told to provide a co-sponsor - the fact that both me and my wife work in the UK and can't show a large savings (though we do earn reasonable salaries) means that they'd like someone established in the US to guarantee that they'll help out if things get tough.

So I'm one letter away from a green card - I don't even need to go for another interview, all I need to do is send in my passport and a new I-386 form + supporting documentation.

Here's the difficulty - A friend just informed me that when I do get the green card, I'll be expected to move to the US within 6 months, AND LIVE THERE!

I'm so not ready to move to the US and start another immigrant process at the moment - what I was expecting was a green card, then a return to the UK to stay for the next two years or so, until I got a UK passport and the economy recovered. Moving to the US at the moment is simply not an option. Can someone please advise what to do next - Is it possible to get the green card and still reside outside the US for the next two years? Or should I just forgo the final step and re-apply for the green card when I'm ready to move? Any assistance will be appreciated.

Once you receive the green card you can apply for a re-entry permit, form I-131. If approved, this would give you two years maximum in which to legally reside outside the US. The application has to be made from inside the US, from a US address. You will have to wait 4-8 weeks after submitting the application to go to a biometrics appointment at your local immigration application support center. On the application you can specifiy to have your approved re-entry permit sent to a US consulate anywhere in thew world.
Careful: you need to be in the US to apply for this, and you need to stay in the US for the biometrics appointment