Hi Mark
You lucky bugger
I've been away so have just read your post.
Trump's Malta- Prehistory and Temples is an invaluable guide to both Malta and Gozo it's probably all you'll need, it's small anough to carry around and won't break the bank.
I would also recommend that you book a tour of the Hypogeum as soon as possible, to miss it would be a tragedy.
If you drop me a line at fitzcoraldo at hotmail dot com I'll send you a zip- full of stuff that I've copied off the WWW.
cheers
fitz