HELP; RRC won't start

oK, here is the situation. This is the second time it has done it.
Monday: Go to Rover, attempt to start it, nothing, just clicks. Won;t even turn over. Move the gearshift around, leave it in Park, try again, nothing.
Boost it with my other car. Try again, nothing. Then I put it in Neutral and it was fine! No problems after that with starting in Park, or starting at all.
Drove it all day monday, tuesday no problems.
Then today, this morning, same thing. Try to start it, nothing just clicks. There is some power(as deck, etc work). Tried putting it in Neutral, won't start in it either.
Haven't had a chance to boost it yet, as I had to go to work.
Now, I am thinking
a) it is the battery, it has been cold around here, and the battery is not doing its thing, and is weak or w/e,
B) Something somewhere is fucked up, WHAT?
I felt the door locks to see if they were warm, but they aren't so that isn't draining my battery.
what else could it be?
I am thinking of getting another battery and seeing if that helps my situation.
BTW, the alternator is several months old, so I don't think it has anythign to do with that.
Thanks.

It is just one click.

No Dice.
Tried the battery terminals, treid boosting it,and trying tapping on the starter(which is in a shitty place).
Won't do more than click.
Currently trying to find a place that specializes in these beasts.

I have ordered a new starter.
Currently it starts after my friend gave the starter a good hammering.