I just got it from Vault 13 by helping deathclaws. I found Hakunin dying and telling about the raid but I don't get xp and quest isn't marked as done. Is there something wrong or do I need to do more stuff?
This happens when you either locate the GECK, or if time runs out. You need to rescue your tribe at this point in order to complete the main quest.
To rescue your tribe, start by going to San Francisco.
San Francisco is located in the bottom left corner of the world map.
In San Francisco, you must find a way to get the tanker (large boat) operational.
You can only go to this place once, and once there you cannot leave until you've finished rescuing your tribe. Prepare yourself before going.
Major Plot spoilers:
Rescuing your tribe and escaping The Enclave will complete the game and display the final cinematic showing the outcomes of the different locations in Fallout 2 based on what quests you did or did not do.
You can keep playing the game as long as you want after completing this.