Is there a plug in for credit card charges to be converted automatically into bitcoin
No, and there likely will never be. The reason for this is that bitcoin transactions (and all other crypto currencies as far as I know) are none reversible while credit cards transactions are, for up to about a month at most banks. This means that if someone buys bitcoins with stolen credit card information and you give them the bitcoins, and then a week later the bank tells you the transaction was fraudulent, you will have to return the money, but you are never getting the bitcoins back. 

A way around this would be for the seller to hold on to the bitcoins for a month and wait for the credit card transactions to definitely go through before dispersing the coins, but with the price of bitcoin as volatile as it is, I don't see this happening.