It is really hard to say if that is possible just because I cannot find what motherboard is in that PC in the first place, and being a laptop are you positive that you will have the correct tools or even will be able to open it up to do the swap, as I doubt that dell will help you out and doing so will void any warranty you have. If it turns out you can swap you may have to pay someone to do it for you. Another problem is that I have yet to find a supplier of the mobile i7 CPU's.
I may be easier and cheaper just to sell the laptop and buy something else that performs the way you want it to.
I know thats not what your looking for but I hope it helps a little.