As soon as you leave Telos travel to Nar Shaddaa. Once there proceed into the central area and find the zoning door to the Docks. Halfway across the Docks will be a door that leads to the Flophouse. Go to the end of the hallway of this flophouse and the second to last door has a guy named Lootra. Taunt him into attacking. Also note that any characters you can have in your party at this point will lose influence with you if they are with you when you kill him, so go alone. His corpse will have a lightsaber part, there is a quest that as a reward he gives this part to you but the dark side gain is minimal even for lightside characters. Next if your alignment bar is about 25% good or bad you can return to the Ebon Hawk for a special fight which will get you the last lightsaber part. If you are not 25% good or bad there are tons of things to do in Nar Shaddaa to get the last of the points you need.(If you do not have a colored lightsaber crystal the merchant Geeda will have one you can buy so don't scare her away) Now talk to Bao-Dur to have your saber made.