Repairing Replacing Starters?

I have a starter in my 03 Saturn Ion, and I think it is slipping. I have the symptoms of a dead battery but I can get the car started after a few minutes of tries. The problem is intermittent. I have good luck when I drive and not have the radio on. It seems to come to life properly. This morning I had a problem starting (used radio) and I got a jump from someone. After they jumped me I still could not start until a few minutes after they left. My questions are as follows
1) should I have my starter replaced?
2) Can someone with “some” mechanical knowledge change a starter on his own?
3) can a starter be repaired?
4) could it have something to do with the wiring
Any other areas that people can point to me would be great. I am going to pick up a Haynes manual next paycheck.