Question of Expired Study Permit

[FalconIA]

Now I'm taking courses in Canada, but I found the study permit is expired for 8 months.(I remembered a wrong expired date.)

I asked CIC, they said i should go back to china and apply the study permit again.

My question is:

Could I ask my friends in china to apply for me?

What should I prepare for the study permit if I go back to apply it?

How long could I get the study permit and visa after I go back?

Thank you so much!