You can find the bow during the quest where ebron chief asks you to clear bandits in the forest. On East side of village there is a Forest , head further East , There will be a couple of bandits near a camp fire, beat them & loot the place. Then head further East & you can see their Camp , sneak to the backside , this will trigger an animation where part members surround & attack the bandits . Make sure that you loot everything , even the tents , most of them will say "nothing interesting" but one of them has a bunch of potions. After Finishing this Quest you must have also completed mirel's bow quest as well.
To be precise, if you take the path east in Ebron to get to the forest, the bow is in a red chest in the top right corner behind the spot where the Earthspirit is blocking the way at first.
You need to talk to the chief in aldyn , he is in the blacksmith shop , after you talked to him ,he will wait at South of vegetable shop (left bottom corner of the Aldyn map) , Talk to him again & he'll show you Ebron.
Where is Ebron ?