You may want to look at this site (it does contain spoilers however).
Desdemona's Beyond Divinity site On that site, you will be able to see where the summoning dolls are, as well as what you need to do to get them.
To gain more experience to kill the Death kights, you can go to the Battle fields and either fight monsters there, until you have enough experience to kill the Death knights, or buy more potions and better weapons to help.