Using miles to upgrade

Hi,
I hope some can help answer a couple of questions.

I have nearly 100000 miles.
I believe that I can use these to upgrade from an Economy to either PE or UC (2 people)
If this is the case, how many miles do I need?
I think I have to but a certain fare of economy ticket - can anyone advise on this and how I go about getting these?
Does there need to be G availability if this is possible? or is G just for outright bookings with points?

Sorry for the questions.

Thanks

[Neil]

It is 50k per person, round trip, to upgrade from economy to Upper.
You need to be booked in an economy fare code that is upgradable, the lowest one is an M. There also needs to be G reward availability to upgrade, and you will have to pay the taxes based on an UC seat.

Thank you Neil.