i think the pot might be a 10k one, usually in the radios, this is what it is used.
if u plan in using a resisotor then the signal in and signal out should be connected together and then connected with the resistor to the ground.
probebly the middle pin is the OUT and one of the pins from the edge is the ground and the other is the signal in
like you say
1 2 3
| | | />max
o o o /
------->
if you get more volume when you turn the pot counterclockwise then u need to connect cogether 2 & 3 & the resistor and the othe pin of the resistor wound be connected to 1 wich should be the ground.(1,2&3 are the pins) try more resistor values....
and can u send a picture of the pot.
usually when you unscrew the knob u would find the value there, near the place where the screw comes, somathing like 10K, 25K etc.