Simply acknowledging the source of a copyrighted work does not substitute for obtaining permission. If the factors of fair use do not evaluate in your favor, do the right thing and ask the copyright holder for permission to use their work.
If you know who the copyright owner is, you may contact them directly. Publishers' websites are often very helpful with this process. Some even have forms for submitting a permission request.
The U.S. Copyright Office cannot give permission to use a work. They can, however, help search for the copyright holder.