1) How do you get a helmet?
You can get them from quest that are none slotted, from players who are selling them in shops or AH, or by buying ap, from the item mall, that are slotted helms.
2) Where is the asmo?
Asmo is located in Cornwell's Ruin in map 1.
3) How have children at lvl 20 and have a cape?
People who you see that have capes at lvl 20 have gotten ahold of the
lvl 16 Victory capes that you can get from a player or vy purchasing AP and obtaining it from the item mall.