It is not clear what you have tried so far, but step-by-step you want to do something along the lines of this:
- In Multibit create a new receiving address by clicking the "New" button.
- On Coin Cafe look for a "Send Bitcoins" or "Withdraw Bitcoins" option.
- Check out any help provided on this option, to see if there is a fee for the withdrawal.
- The "Withdrawal option" should allow you to specify a destination and an amount: Put the "receiving address" you created in Multibit as destination, and (if there is a fee for the withdrawal)
your balance - fee as the amount.
- Confirm the transaction/withdrawal
If you cannot find a withdrawal option, check out the help section, or get in touch with Coin Cafe's customer service: They provide a live chat, service email address and phone number.