Please look to add quality fans like Noctua or the like. A little bit more pricey but if quiet with great performance is what you desire then look no further. Please add this fan to your PSU if possible otherwise you likely will have fan headers on the motherboard to use but here again a picture of your mobo and computer case inside would be of great help !
You can also add a fan splitter cable to your existing front case fan and run both off one power plug from your PSU if that is how it's set up. The Noctua's are so quiet it will be fine to run them wide open but Noctua also provides resistors to reduce speed and noise even lower. Cheers, the Cheese