I know there's been a thread about this before, but I can't find it. Oh well.
Basically becuase you are on a shared server there is no way for you to change the time the server has. Such a change would effect every one else on that server, whcich obviously wouldn't work.
Now, if you're using some kind of a script or program you may be able to change it so that it displays the correct time for you, however I'd have to know what kind of script/program/system your using to be able to tell you how to go about to doing that.