Mike - I'd try using a pure sine wave inverter (rather than a cheaper modified sine) off your car battery or another 12v power source that you might have access to.
Here's a 300w unit from Tricky's for $144 that'd do the job admirably (plus you can use it for plenty of other things such as charging your phone or whatever other 240v appliances you have):
I have a couple of Projecta Laptop power adaptors, they have a adjustable voltage selector to suit any laptop, you can get them from most Auto Parts stores for around $60. I use one on my Laptop and one to Power My Meade LX200 off my feild battery, they have 15, 16, 18. 19. 20, 22, 24, volt settings at 3.5 amps.