AVR-Chat

hi dears.
i am a new avr user that i should make a digital clock and calender 
for my project.
at the first,i need to make 1 second delay.i have to use timer 
counters but i could make it only for 1 milisecond!
should i use a nother crystal(32.768KH) for it? 
please help me for do this.
thnx alot
bye