FlyerTalk Evangelist and Ambassador: The British Airways Club
Join Date: Jun 2008
Location: Somewhere between 0 and 13,000 metres high
Programs: AF/KL Life Plat, BA GGL+GfL, ALL Diam, Hilton Diam, Marriott Gold, blablablah, etc
Posts: 33,191
(1) As already mentioned by others, try kayak or equivalent with a flexible search (no specified airline, date +/- 3 days, etc)
(2) Obviously also check as return flight (with a plan to 'waste' the return as this will likely be cheaper than the one way.
(3) That sort of itinerary with that sort of urgency can only be expensive.