Prior post is incorrect. In California, you have 30 calendar days from service. Service is when you receive the summons. To meet the 30 day deadline, you need to physically file your response with the Court within 30 day. It is not 30 days from the postmark. If you need additional time, contact the attorney on the papers and request additional time. If agreed to, be sure to confirm the extension of time in writing. The best approach is not to wait until the last day to get your response on file.
If you need a referral to an attorney, contact the Alameda Bar Association and ask them to provide you with a referral.
Without knowing the specifics of your case, it is difficult to comment with precision. That being said, the instructions on the summons should govern your response time, and your response time is triggered by service of the summons -- not by the date on the summons. The date on the summons is relevant because, if the summons is not served within a specified period of time, it may become stale, depending on the specific rules of your particular jurisdiction. Filing of the responsive pleading (answer or motion, as the case may be) is accomplished by delivery of the responsive pleading to the clerk of court. Putting the responsive pleading in the mail is insufficient, and the prudent practice is to actually have the responsive pleading hand delivered to the clerk of court, who can provide you with a date stamped copy evidencing the filing of the responsive pleading for your files. In the event that a default is entered, most jurisdictions provide a period of time from the date of default within which to explain to the court why a responsive pleading was not filed and, provided that there is good cause for the failure to file and that you have a defense to the suit, under most circumstances, the default should be vacated as a matter of course.