290k Velocity points could get you to New York 1 way for 2 with the following
Virgin Australia (Business)
SYD-LAX =95500 Velocity
LAX-JFK = 49500 Velocity
280k Velocity gets you 207k Krisflyer - Could only get you so far too.
Australia-Europe=80750 (112625) Krisflyer (incl 15% online discount)
Australia-New York=85000 (119000) Krisflyer
You best option is probably using your $4000 flight centre voucher to buy economy tickets and upgrade with your points.
SYD-LHR Economy $1000 1 way per person
SYD-LAX Economy $1300 1 way per person
SYD-LAX Economy $1500 1 way per person
Australia-Europe 75000 Krisflyer (not incl. online discount)
Australia-USA West Coast 75000
Upgrade Business- First
Australia-Europe 77500 Krisflyer (not incl. online discount)
Australia-USA West Coast 77500
Bear in mind that availability of flights are very low.