Try jump starting it, if it turns over faster hooked to another battery, then I'd say it was time for a new battery. HTH
Yes and no. If you are getting a faster spin on the starter by jump starting, you could have a bad battery or you could just have dirty cable ends.

Will, when you checked the voltage of the battery, did you put your meter on the battery posts, or on the cable ends? If you put it on the posts then you got a false reading of sorts. You should check the voltage both ways; on the posts and on the cable ends to see if you are getting a voltage drop indicating a bad connection.
I'd pull the cables off and make sure that they are clean and tight and then check the battery while they are unhooked. If the battery shows good while they are unhooked, and you are certain that your connections are clean and tight, then I'd say that you may need a battery. Next step would be to take the car to a parts house and have them do a full system test on the battery, starting and charging system. You very well could have a bad cell in that battery.
