If you're not sure what motherboard you have it would help to download a program like CPU-Z to find out. [url]http://www.cpuid.com/softwares/cpu-z.html#gallery[/URL]
Download CPU-Z and either post the information in the mainboard tab or take a screenshot and post it up here.
You're current CPU fits in an AM2 socket, but your motherboard may be AM2+, meaning you may have more options.