your motor is a v6, so it has 2 heads, the head that has cylinder 1 is bank 1, the head that has cylinder 2 is bank 2, sensor 1 means before the cat, sensor 2 means after the cat, so bank 1 sensor 1 would be before the cat, on the exhaust manifold where cylinder 1 is. on your car cylinder 1 is on the passenger side near the fire wall, the firing order is 1-2-3-4-5-6 , toward the firewall is cylinders 1, 3, & 5, in the front of the engine starting from passenger side to driver is 2, 4 ,& 6. bank 1 sensor 1 is BEFORE the cat near the firewall , and don't use cheap ass bosch universals that you have to wire in unless you know how to do it #1, #2 if you changed the correct sensor you probably didn't wire it right, you can get a denso oe replacement for not that much #3 the problem may not be the sensor you could have a damaged wire or short in the heater circuit....good luck
Denso Part # 2344622 ( non-california model ) $200.70 suggested list price ( i can get you one a little over my cost, not this list price, if you want ^_^ )