The best bow would probably be the Bow of Hilfin (quest reward in the Dark Forest), but the stats are random, so you may find better ones for sale. I don't think there is a crossbow consistently in the game, so you would need to rely on random drops or purchases.

There are several topics on swords. For one handed swords consistently in the game, the best damage range you can get is 71-100, but you can find slightly higher damage on ones for sale.

Whats your favorite sword

WHAT IS THE BEST SWORD I CAN GET

One Handed Sword