You were rescued from the clutches of the Wight-lord by Tom Bombadil, but you learned much that may help Strider and his people.
'Old Barrow-wights from Angmar came. They disturb the peace and trouble folk who wander through their mounds. Let the Dead sleep and leave their troubles in the earth. Unless of course you wake them, dancing on their rooftops!
'Hey, come, my friend. Linger here no longer. To Bree you should be a-going. You've a friend there who awaits you!'
Strider awaits your return in his room at The Prancing Pony in Bree. The entrance leading from the Barrow-downs to the Great East Road is to the north.
Travel back to Bree and tell Strider what you learned of the Witch-king's plans.
Barliman Butterbur serves his guests in the common room of The Prancing Pony.
You travelled back to The Prancing Pony, but you found the door to Strider's room locked. You should speak to Barliman Butterbur to learn if he can tell you where Strider has gone.
Gandalf's room in The Prancing Pony Inn in Bree is found by taking a left out of the common room, until you can only bear right. The room is at the top of the stairs at the end of the hall.
Barliman Butterbur told you that Strider has left The Prancing Pony, but that Gandalf, a Wizard by reputation, arrived and asked to speak to any who were looking for the Ranger. You should speak to Gandalf and tell him what you have learned.