i7 CPU upgrade for N7010

I have the Dell Inspiron 17R (n7010), service tag<ADMIN NOTE: Service tag removed per privacy policy>, laptop with the Intel Pentium (R) P6100 @ 2.00GHz. I'm looking to upgrade the processor and need help on some options. I was originally looking at the i5-480m and read that it would fit my chipset, however, recently I've been looking at the i7-620m or i7-640m. I'm not sure if an i7 processor would work with my system or what the differences between the two are. Can anyone tell me what the differences are or whether I can fit an i7 into my laptop. Thanks