While it is possible, you would be limited to the supported CPUs -- and the bios and chipset will support up to an i7 2670QM for that model. You can also upgrade the memory to 2x8GB, and an SSD or larger HDD.
If you cannot find that CPU, the i7 2720QM also works.
Also note that you need to update the bios to at least version 214 to support the 17-2670, you can get that and all other drivers from ASUS support. I would think that you would move to 64 bit Windows 7 if you are using 32 bit.