I am a third year PhD Student in math. I am studying abroad from my country. I need some advice.

I have three main problems that I would like to share with you. 

1) It seems, I will be graduated with 1 published paper. As you know, finding postdoc position is so difficult even though I would really like to keep doing research in mathematics. Do you have any advice to me for 1 year left of my PhD so that I can get postdoc position easier than now?

2) My supervisor would not like to work with me. Moreover, he is so busy. Whenever I can ask questions from him, he thought about my questions at that moment, not anymore. 

I found out I have to work by myself. Unfortunately, I do not have enough experience to work myself and I need to work with someone. I decided to work some mathematician who I met them in some conference. I had some bad experience. Would you please tell me how can I talk to some mathematician so that we make a paper together? In particular, I will meet a great mathematician that I have been following his work since 2017. I made some progress and i would like to show him and convince him to work with me.

3) How much I am good in my field, I am terrible in other branches of mathematics. Let me give an example that show that my question clear. I do high level things in mathematics but I forgot some basic things from other branches that I have learnt several years ago, such as graph, Algebra,number theory,... Is it bad things? What is your advice?