I just wanted to know if i could upgrade to a better wifi card than a Realtek RTL8111 – GigabitOn my intel h67 chipset. I have seen no performance change after upgrading my network
If you are getting 150Mbit link rate then you are maxing out that card. Your laptop (you didn't specify desktop or laptop) may only have one antenna so a dual stream card won't benefit you.
So knowing that I have a lower end card only makes me want to upgrade the hardware even more so. Is it possible to just upgrade my card ( it is a desktop: fx6860 ur20p) to a better dual channel card, because I just upgraded to a dual channel router.