Once you've adventured out into the Spider Forest a bit, talk to Cain and he'll start you on the main quest for the Act, Khalim's Will. It's a four-part quest to once again grab components that you need to put together in the Horadric Cube. In doing so, you'll complete Quest
7 and be prepped for Quest 8.
Khalim's Eye - This can be found in the Spider Cavern, within the Spider Forest. Go down into the cavern and kill the spiders that guard it. It's in a chest.