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To my knowledge, credit cards don't hold amounts. They may hold limits, and current balances (therefore finding out how much the person can spend), but that is sensitive data that you won't be able to find out...
As feyd I would advice for 3rd party processing. If you have your own merchant account it is not that expensive. There are dozens of companies out there so do a comparison.
You could do it yourself but you need a lot of money to incorporate a system that is even close to secure.