Liam,
Yes, you'll need to purchase a new copy. I believe it's the same for all of the VFR flight guides - Pooleys, AFE, Jeppesen, Rapid etc.
Pooleys do have a habit of changing their ring-binding system from year to year, so you may need to buy a new binder as well. Haven't seen this year's yet though, so can't confirm if the holes are in the same place as '08's version or not.
jez