i think the price of insurance depends on your years of riding,
it will go down for 2nd year and so on. you can either buy your
insurance through:
1. any motor shop. most of them do help people do. use this to save
the trouble but might have to pay a bit more.
2. go and find the insurance company yourself. i got mine through
this way.
as in how long b4 you need to do the documentation, it shouldn't
matter, since the day of renewal starts from the day your old
insurance expired.