MAC LOST PARTITION HELP!!!!!!?

Guys yesterday i had made a 40 gb partition on my main harddrive using bootcamp for installing windows but i mistakenly deleted that partition with disk utility and now it is unallocated and i am not able to increase my main partition size and recover unallocated partition - when i try to increase partition , disk utility does not allow me to apply the changes ..... I REALLY NEED YOUR HELP >>>>>> THANK