Can't purchase, but it can absolutely be repaired. This is actually a somewhat normal thing and it requires only basic techniques - but you will need to do some fiberglassing - still pretty basic, though. Essentially, cut the underskin off... remove the plywood core... epoxy the new core back on... glass a new skin over the core.
That's the basics. Before going into specifics, though, please search through the forums - there have been quite a few of us that have done this and have gone into much more detail in other threads. Find those threads for you? Nope - I don't do homework for others!
Besides, searching is searching is searching and you can find them in the same amount of time as I could. You can also search the whole internet - the process is exactly the same regardless of boat "brand"
On a different topic... welcome aboard!