MP is correct. You do not automatically get upgraded when redeeming miles. The upgrades are capacity controlled and not always available.
Did you ask about other routings (i.e. SYD-SFO-ORD-IAD?) I guess now that it's booked, it's a bit late, as you'd have to pay to change to more open flights.
You willl need to check your status yourself. MP rarely, if ever, call to say you've cleared. Most of us on FT have an upgrade OC disorder and will check every day! At least united.com does generally show you've cleared.
I would guess you'd be OK on the 763 flight. They'll probably open up some inventory a few months before hand. The 319 flight will be a toughie, as even 1K/UGS fail to get upgrades on this flight.
I'd call about every two weeks to see how you've progressed.
Do you have any status at all with UA?