Upstream O2 sensor ripped out - how to replace?

Somehow my upstream O2 sensor seems to have gotten caught on my axel and ripped out. The housing on the upper connection is broken and one of the pins was stripped off its wire (the other 3 are still attached). The sensor itself is still plugged in, but I figure I'll replace it since it's been a while. But when I search for O2 sensors, I'm coming up with plenty of options for the parts I have, but not what I need to replace. How do I go about finding the male connector for the top where the sensor plugs into the rest of the engine? And how do I know which wires go where? I still have the one pin that got stripped, and can rewire it. But what order do they go in and how do I find their casing replacement?