How do I reset the advanced time settings on my Mac?

I changed the time settings manually a while ago, and then back again, which seemed like no problem. However, all my files are now stamped with the time I changed it to manually. I sync my Mac with the schedule for my University lectures, but even this only shows the time that I changed my Mac to a while ago. Is there a way to fix this? I don't know what I did, but I managed to set the time settings in the advanced panel to 7 am.