That is the way that it is. The only way to get around this is to have something like DVDs with different regions... and please please, lets not go there!
Exchange rates are a fact of life for most of us. In New Zealand you wait for the NZD to get strong and buy from amazon... When it is weak, you put some in savings (waiting for the next strong time).
Listen, the USD could get weak (and some have forecast as much), then you get Win7 on the cheap in the UK.
Do the free upgrade or wait for the USD to weaken... makes for an interesting exec meeting I am sure...