"In text, give the popular or official name of the act (if any) and the year of the act." (Publication Manual of the APA, 2010, p.219)
"In the reference list entry, include the source and section number of the statute, and in parentheses, give the publication date of the statutory compilation, which may be different from the year in the name of the act. (Publication Manual of the APA, 2010, p.219)
Explanation: In the example above, Pub. L. No. 109-58 refers to Public Law number 58 from the 109th Congress, as it appears in volume 119, page 594 of the US Statutes at Large (119 Stat. 594).
Here's how it might look if you are citing to where it can be found in the United States Code: