College Affordability Act of 2013 - Amends the Internal Revenue Code to replace the Hope Scholarship and Lifetime Learning tax credits with a new American Opportunity Tax Credit that allows: (1) a 100% income tax credit, up to $2,500 in a taxable year, of the qualified tuition and related expenses (i.e., tuition, fees, and course materials) of a student at an institution of higher education who is carrying at least one half of a normal full-time work load; (2) a life-time aggregate credit amount of up to $10,000; and (3) refundability of a portion of such credit. Denies such credit to students who are convicted of a federal or state felony offense involving the possession or distribution of a controlled substance.

Allows an exclusion from gross income of any amount received as a Federal Pell Grant.

Establishes programs for: (1) periodic payments to students as qualified expenses are incurred during the taxable year, and (2) informing the public of the availability of the American Opportunity Tax Credit.