buddy - you HAVE to get car seats for kids. i am sure i dont need to impress upon you the safety angle after so many other PWs have replied but google it and there is enough empirical data to suggest that you need to have them.
i would only install on the rear seats and since you're in Lahore goto AlFatah or that big baby/kid store in liberty. most good seats will only install on 3 point seat belts (not 2 point lap belts) so depending on what car you have you may have to look into adding seat belts as well. i am only saying that because quite a few popular cars in PK dont have proper 3 way belts in the back.
BTW most good brand car seats will have their manuals/user guide online so look that up if you dont get a guide from the seller, as is the case mostly from stores like alfatah who throw away the box beforehand.
oh yeah last peace of advice - most people here (unfortunately) think you're an idiot if you use that baby seat and have no problem pointing it out. dont worry about them, let them do it... its YOUR kid!