you could take a taxi 45 minutes before your flight if you want, but not sure i'd recommend it.
the closest to flight time i've heard any professional car service say is 2 hours before flight.
you have about 30 mins from WDW property to OIA, pad that a bit from WL to even get to where it's 30 mins, maybe 50-60 mins. consider you need to check-in including any checked bags if you haven't already done so through a participating airline at the resort... get through security.. take the tram... get to your gate.
i'd say 2 hours is right on the edge. granted with DME, i've pretty much always ended up with like an hour to spare, you never know what's going to happen.
and it's not like OIA is a horrible airport to be stuck in for an hour.
i'm guessing the cab might run you $40-50 or so, given its metered. i believe one private car service i can think of is $60 one way