this will help...
today = [NSDate date];
dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"MM/dd/yyyy :EEEE"];
dateString = [dateFormat stringFromDate:today];
NSLog(@"date: %@", dateString);
[dateFormat release];
gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
components = [gregorian components:NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:today];
[компоненты setDay: ([день компонентов] - ([день недели компонентов] -2))];
NSDate *lastDayofweek = [gregorian dateFromComponents:components1];
NSDateFormatter *dateFormat_last = [[NSDateFormatter alloc] init];
[dateFormat_last setDateFormat:@"MMMM d,yyyy"];
NSString *dateString_last = [dateFormat_last stringFromDate:lastDayofweek];
[dateFormat_last autorelease];
NSDate *beginningOfWeek = [gregorian dateFromComponents:components];
NSDateFormatter *dateFormat_first = [[NSDateFormatter alloc] init];
[dateFormat_first setDateFormat:@"MMMM d,yyyy"];
NSString *dateString_first = [dateFormat_first stringFromDate:beginningOfWeek];
[dateFormat_first autorelease];