CrossbowsFollow

From now till 60 farm honor and honor marks. Once you hit 60 get the High Warlords Recruve. Use this bow till 70 when you can get Valanos' Longbow. Once decently geared, get the Sunfury Bow of the Phoenix from Prince Malchezaar (the last boss of Karazhan). If you manage this then your are set on weapons for quite some time.