Ten months after the American retailers won a lobbying victory on Capitol Hill against debit card swipe fees, a trade group representing convenience stores is pushing for the government to crack down on similar fees for credit cards. According to a new report from the National Association of Convenience Stores, swipe fees were adding roughly 7 cents per gallon to the price of gas at the beginning of April, with credit card swipe fees alone costing convenience stores $11.1 billion in 2011.