You can get a Life time warrenty start from autozone. The remanufactured starters from autozone will last anywhere from 2-3 years. If you don't mind unbolting it then these starters are okay (due to warrenty). If however, you don't want do deal with it, then go to napa or better parts stores.

It does sound like it is your starter, you can take it to Autozone and have them bench test it to make sure.