Water Pump - Sump Style
Submersible Utility Pump - Superior Pump 91250 1/4 HP Thermoplastic
Available from for about $47 from http://www.amazon.com/dp/B000X05G1A/ref=pe_385040_30332190_TE_M3T1_ST1_dp_1 .
Here's a lower power pump...
Wayne RUP160 1/6-Horsepower 3,000 GPH Oilless Submersible Utility Water Pump
This one is nice because it has an energy efficient motor. Only 1/6HP but can pump 1850 gallons per hour up to a head of 10 feet.