You need an AC to DC CONVERTER.
CHEAP way: Wire up the pump to one of these
Easy & versatile way that costs a little more:
Get one of those battery jumpers that will power 12vDC stuff. Just leave it plugged in and the pump hooked to it. UPSIDE is that if your vehicles battery dies, you have a jumper right there already charged up!
More expensive and complicated:
Why don't you pick up a cheap battery from Wal mart (we use the starter battery for the bus...might as well use it than let it sit) and run the pump directly off the battery? That's how we do ours. We use a cheap battery charger
every couple of weeks to charge the battery over night. Been doing this for a couple of years now. It's not like you need a big battery bank.Nor do you need an expensive deep cycle battery. You just need a single 12vDC battery and a way to charge it. You may need to replace the battery in about 5 years rather than the 7 years you get from better "real" deep cycles. Better yet, swap the battery out before the replacement time runs out.
Personally If we did it over again we would use the 2nd method (power jumper) But we had the battery and did not want it to die from sitting. And we picked up the charger from Wal-mart one day. Prior to that, David charged the cart battery by hooking it to the Jeep. Or placing it in the bus to crank the bus up once a month.