You cannot install the Pentium it is an LGA1150 processor while your motherboard must have an LGA775 socket if you have a Q6600. Quite frankly there is no upgrade path for this motherboard.
Better off to save up and buy a whole new computer. If you want to give a budget I can propose a build. I will need country you live in (makes a difference to price and availability), your budget and what tower size you want (Full tower, Mid Tower, Micro Tower). And if you have a preferred online vendor, state that as well.