REQUEST: MIA to LHR London in late Dec Flight & Hotel

Looking to get to the O2 in late December during my vacation. I want 4 -5 days or so during those last two weeks of the year. I can leave as early as 12/20 and must return by 1/2/10.

1 adult
MIA to LHR (willing to leave out of FLL, MCO or Tampa too)
4-5 nights requested
Main goal is to see the MJ exhibition at the O2 and maybe Thriller Live! too.
Travel budget: $1500.00 US including flight and hotel. No car, wanna be in walking distance to stuff and tube.

Research: CheapTickets.com seems to show the best deal including all fees (except AA baggage fee) with a price of $1580 with American Airlines. This includes RT Mia to LHR on 12/25 8:30pm non-stop returning on 12/31 12:00 LHR to MIA via Raleigh-Durham. Hotel deal was 5 nights @ the Cavendish. Maybe I could save more with a promotion code for CheapTickets? anyone have one?

Prices heading up? better deals out there? This is my first trip to London.