Open Question: I want to purchase alert pay dollars using credit card - tell me about charges !?

Dear Friends by using my credit card i wanted to purchase dollars to my alert pay account. I have city bank credit card. Kindly tell me what will be the charges from bank and Finally for what price i can purchase dollars. If i purchase 5 $ or if i purchase 50$ the bank charges the same fee for both or difference. If u have purchased dollars using credit card. What is the cost for 1$ including bank charges. Kindly answer my question at the earliest