If your meleeing then definatly use the defender. If your constantly using prayer or are maging/ranging then you should use a prayer book. Zammy book gives +8 attack bonus to all attack types and styles Sara book gives +8 defence bonus to all defence types and styles And Gutix gives +4 attack bonus and +4 defence bonus.
For glarials ammy check the chest down at the grave of Glarial. For the key, you should be able to get that back from the book. So if you can't then you must have it somewhere in your bank.
You need about 1 nat per graveyard point. And 3 nats per alchemy point. You need 200 graveyard points and 300 alchemy points. So that totals to about 1100 nats.
Look in your bank, maybe the key is there. It's a tradeble key, so you might just have picked it up from the ground sometime. It was the same for me, I couldn't get the key from the guy, then found out it was amongst the junk in my bank. I had picked it up from the ground.
The boss uses all attack styles. Though range is the one that he uses the least. But whatch out, the range attack does a massive 9 damage poison. So don't forget to take an anti poison.
Papaya seeds are 30-40k Yew seeds 60-70k Palm seeds 60-85k Magic tree seeds 150-170k There are some more seeds that are worth around 30k. But these are the most expensive ones.