First Responders Funding Reform Act of 2003 - Amends the USA PATRIOT Act to require: (1) that each State be allocated in each fiscal year not less than .5 percent (currently, .75 percent) of the total amount appropriated for domestic preparedness grants; (2) such grants to be awarded based on a quantitative risk assessment for threat, vulnerability, and consequences; and (3) the Office for State and Local Domestic Preparedness Support of the Office of Justice Programs, by March 1 of each year, to submit that assessment to Congress.