Starting issue. Bad starter?

[Renesisking]

just hit a hiccup in my plan for the winter. The car doesn't start....

Two weeks ago I had trouble turning it on and it was misfiring like a bitch. It felt like a 4-cyl running on 3. It quickly subsided and was back to normal, revved freely and eagerly as it should. Its been a week since I drove it as I wasn't feeling well and I don't take the car out often in the winter. Today, it didn't want to start at all. I even tried to jump it and it was a no go. It now sits half way up my drive way. I called up the dealership and they said that the rotors could be seized (i.e. no oil and over heated) which doesn't make sense as the car has plenty of oil and has been running less than 206 degrees. I'm thinking its just the starter but I would like to make sure. I don't know if I should take it to the Mazda dealership or have my buddy's shop take a look at it. Any advice? Also, how do you start a car with a bad starter? I did it with an older car but the starter wasn't underneath the car like it is mine. Do I still tap on it while someone is cranking it?