93' Subaru Legacy, not starting. ALT/Fuel?

93' Subaru Legacy; 130K; 4 cylinder. Since it has been getting cold out my car has been starting hard and wanting to die as I let it idle and warm up. It wasn't having any startup problems besides not wanting to continue idleing. Then a week ago my car refused to start up once, I thought it was an isolated incident as it didn't happen again till today. Now, the car is REFUSING to start. I have an engine code that points to the oxygen sensor, but I don't know if that could cause the car to not start. I'm thinking the problem is the alternator or the fuel pump(or some fuel system). Read next para

When I start up the car, it starts up like it always does and sounds the same for the first second. Then, it seems like it loses its initial starting power and just dies down from there. If I try it again afterwards it seems to not have much starting power and the same thing happens. I also hear the same stripping sound that occurs when you hold the key in the ignition position for too long. The belts seem to be in great condition so I doubt its them.

I really need to get this problem fixed soon. Thanks guys.