In other words load up http://192.168.1.1/Tools/Time.shtml .
First pick your correct time zone. Leave "Enable Daylight Saving" unchecked for now.
Check "Enable NTP Server" and pick either server. Then click "save settings". Wait 10 seconds to see if time is correct.
If it's off then check "Enable Daylight Saving". And pick the correct "Offset" and once again click on save "settings".
If this still does not set the time correct then yes you will need to set the correct time manually or find a different "NTP Server" for your time zone.
http://www.pool.ntp.org/en/ is a good place to start if you need a "NTP Server".