Amends the Public Health Service Act to extend and reauthorize appropriations for Projects for Assistance in Transition from Homelessness, which provide specified services to individuals who: (1) are suffering from serious mental illness, or are suffering from serious mental illness and from substance abuse; and (2) are homeless or at imminent risk of becoming homeless. Revises the minimum state allotment for such program to be the greater of the amount received by the state in FY2010 or $750,000. (Current law sets forth a minimum allotment of $300,000 per state.) Provides that if funds appropriated are insufficient for all states to receive the minimum allotment, then states shall receive no less than the amount they received in FY2010 with additional money spent to give states the minimum of $750,000.