to get the alt off you need to take off the coolant overflow bottle and the intake box thats over the exhaust manifold. because it wont fit out any other way.
i think your going to need 10mm, 13mm and 15mm sockets and an extention
your going to have to loosen the tentsion on the ps/ac belt. should be 2 13mm and 1 15 bolt on the ps
loosen the tentsion on the alt with the 13mm. then unbolt the bottom bracket. should be 3 15mm bolts
if it was warm out i would say maybe half hour to a hour if there is rusted bolts
but being cold as shit out… hour and a half or more
check all the connections first. they usually get corroded with it being right on the bottom. the battery light will come on if the alt belt slips for too long. check the condition of the belt and make sure its tight