Sump Pump hookup in a leaking well...?

I have a well in the country that occasionally fills with water (as much as a foot or so) when it rains a lot. I have no idea where the water is coming from since I have sealed the block walls with UGL DryLok and sealer. So, I thought about installing a sump pump. I'n not that good with electricity, so please excuse my dumbness. I have a 220 volt grey wire coming into the well which powers the pump. It's wired directly into a switch which can turn off the well pump if needed. Is there any way I can wire in an outlet for a sump pump into the existing wiring...especially since it's running at 220v? Or, do I need to run a new wire? Any thoughts on the wiring and/or where water could potentially be coming in would be most helpful. Thanks... sonofbrunhilde....apparently you are without a clue anyways...so don't bother answering people's questions. How many people have a water well in their basement? If I meant a pit, I would have said a pit.