96 Jetta Starter prob?

I have had my Jetta 4 years, never once even hesitated to start, last night I come home from work and come out 10 minutes later, it will not start (won't even turn over). I have a friend come over to jump me, it will not jump. Cleaned the battery terminals, it still will not jump. I get him to pull me and we bump the clutch, it runs fine, and I drive around for 20 minutes. I pull into Auto Zone's parking lot before turning it off, just in case. Try to start right away, nothing. It does click though. The guy plugs in the diagnostics. It is not throwing any codes. He tests the battery, and says that is the problem. Switch it out, nothing, so I guess that rules out battery/alternator. I need a new starter right? And would you suggest that someone like myself who is not very mechanically inclined attempt to switch this out using a Haynes manual? or is this something for someone that knows what they are doing?

Sincerley,
Broke and Broken in Ohio