No, mine is not a dual core. That is why I am wanting to upgrade to a dual core. I had my numbers all mixed up. My motherboard will support an AM2 cpu Amd Athlon 64 x2 4800+ up to 65W, not the 3800+ like I thought. So I wasnt for sure if the 5200 would work although it is the correct wattage and socket. I can't find any good upgrade from my current cpu other than used from ebay. If the 5200 would work that would be the first one I have found one new.
Edit: Mine is M2N68-LA (Ivy) not the Narra. From what I just read the only difference is the amount SATA slots and the memory slots. I just read on another forum than any brisbane cpu will work with the ivy board.