starting issues

ok so I've been having some issues with starting my car recently.
The starter seems to be turning real slow for some reason.
It will normally start when i first go out to start it but will turn slow.
And if I park at the gas station the go to start it again the starter goes even slower and barely turns the car over.
I have a new alternator and when the car is running it is working fine, I checked, so its not the alternator.
I thought it was the battery since the battery has been the same since i bought the car so I bought a new one but still have the problem.
I'm guessing the only thing left is the starter is bad.
Has anyone experienced anything similar or have any other ideas as to what the problem is.

and when i say its the starter is turning slow i mean real slow... rer..............rer..............rer..............rer..............rer. (thats supposed to be what it sounds like)
It actually wouldnt start one time... but luckly i was on a hill.

Thanks
Ryan

well.. like i said the battery is new so I dont think thats the problem.
the connections on the battery arent corroded so that should be fine.
someting i didnt mention is that my battery is relocated to the trunck but i dont think that should cause the problem.
I'm going to check my connections on the starter and if its not that I guess I'll just replace it.