Yeah unfortunately the head to head leagues lock at the start of the season so you won't be able to join one of them until next year. It'll be tough to get a top 10 spot in the classic league (which is where the big prizes are) as you're 6 weeks behind everyone else but you could definitely do some damage in the knock out cup which starts in GW32.
Prizes are
Classic - top 10 team
H2H - 1 Hive for a win in Division 1 / 0.5 Hive for a win in Division 2
Cup - 10 Hive available per round split between all winners in that round
Feels so bad that I missed out on this.. I have almost 400 pts. Which I think is close to top 10. But, since, I am just starting now. It will be difficult to comeback!
I'm sure it will be fun though.. So, I'm glad I knew about it at least now =D