Zelda twilight princess question!?!?!?!?!?!?!?!?

ok im in the forest temple and when i go to room 13 i c the 4th monkey but i cant get it. so i go up and i find a spiderweb in the ground to get to the monkey. but out of my luck i dont have any fuel left in my lantern to burn it!! how do i get lantern for my fuel in the forest temple!!! help -