Can I update my Alienware M17x's Processor?

[laxplaya143]

I got my Alienware M17x about a 1 1/2 yrs ago (just before the i3s, i5s, and i7s came out for laptops. Can I swap my Intel Core 2 Quad 9000s for i5s or i7s or would i have to get a whole new motherboard? Also, how much of a difference would it make?