Mirror Modifier isn't working correctly its offset? Hi guys i'm having a small issue here trying to get my mirror modifier to work, I believe it has something to do with the origin point but being new to blender I don't have the know how to fix this problem. If someone could point me in the right direction that would be incredible.

Thanks guys.

https://drive.google.com/file/d/0B88dKYvqd3wOM1hkbGlYNkhPUk0/view?usp=sharing
Your mesh has been rotated in object mode:



To apply its rotation (i.e. making it retain its orientation while havin the angles all set to zero) use Ctrl+A. 

Read:Why is it important to apply transformation to an objects data?

When you do that, the viewport's axes will match the object internal coordinates and the Mirror modifier will work as you'd expect (you may need to change the axis you're currently using for mirroring)