I have all my coins in on an online trading site

You either have no idea how dangerous storing your coins online is, or you are a seasoned trader who know what he is doing.
No trying to judge hastily I rather think you belong to this first category.
Cold storage or exchange wallet for trading....what else?
Unless you have rather excessive amount of coins then cold storage is rather fancy way of storing coins.
What is wrong with software wallet encrypted with strong password?