3 hours, might be an overstatement when replacing a laptop's processor. But, it's not like replacing a desktop's processor. Your question was simply, "Is it possible 2 upgrade to a better one i5 or i7 ???" and yes it is. Based on the processor, you have now, the motherboard "socket" or chipset is either
Mobile Intel® HM65 Express Chipset
Mobile Intel® HM67 Express Chipset
Mobile Intel® QM67 Express Chipset
Mobile Intel® QS67 Express Chipset
All of which are compatible with both i5 and i7 processors. But, in my opinion, your setup is just fine (obviously, I don't what you're doing with your computer) and I wouldn't risk changing your laptop processor.