Hello all, I am new to the whole Golf owner thing

, and I recently bought a golf, there are a couple questions I have and hopefully one of you will be able to help me out.
1. How can I tell what year my Golf is? I think its an 84, not sure though. (The lady I bought it from was not all there and she doesn't know)

2. How can I tell if its a GTi, or MK2 or anything like that.

3. Is there anyplace online that I can buy older VW model parts?

Again, thank you for your response.