Return to the Ruins of Greyhawk: Help?

[Deth Muncher]

Right. So, my DM decided to try this particular campaign out, although with plenty of his own additions. He doesn't really tell us what is and isn't in the book, but nevertheless, it's still fun. My thing, however, is that I don't know if my group is going to even be able to take the dungeon once we get there.

At this point, we're Level 8, and have just run into another adventuring party, who basically gave us the outline of the three towers, what each of them are, and what's on the ground floor, along with a few spoilers (like, for example, the Magic Tower might have a shortcut to Zagyg's Gauntlet). Currently, our party consists of:
Me: A Human Sorcerer (fire specialty, with Fiendish Heritage, and Fiery Burst reserve)
A LE half-fiend Cleric with ridonkulous Domain spells, like, oh, Greater Darkness. He's got a Ring of Mindshielding, so he turns up grey to our paladin.
The Paladin, who...well, he's kind of a noob, but he's your basic Pally.
We also occasionally have a Gnome Wizard, a Tiefling Rogue, possibly a Blighter (more specifically, Druid5/Fighter1/Blighter2), possibly a Barb6/Frenzied Bzkr/2.

I know we should be Level 9 before we go in. But does anyone have a suggested level that would be slightly better? Also, anyone have a quick way to make 200k gold fairly quickly so i can get a Shield Guardian?