The expiration date of your visa is the last day you may use the visa to enter the United States. It does not indicate how long you may stay in the United States. Your stay is determined by the Department of Homeland Security at your port of entry.
In some circumstances, a person may be released from custody without bail and be given an order to appear, with certain conditions as governed and directed by a court-affiliated agency. Project Remand ('PR'), a Ramsey County pre-trial court service program, is one example of such an agency.
Bail is set by the judge during the defendant's first appearance. For many misdemeanors, bail need not be set. For example, the defendant may be released on the issuance of a citation such as a ticket for a driving violation or when booked for a minor misdemeanor at a police station or jail.