1. Look at what type of chip you have. Google for it. Mainly look for the socket type.
I can see that the chip you have is a AM3 socket.
2. Now go to any PC hardware shopping website and look up AMD motherboards which are of the same socket.
Most common and user-friendly site is www.newegg.com. They have a guided search option which is quite helpful.
Even if you are not from the US. Just note down the model number and brand.
But here it gets a bit tricky...
AM3 socket boards are only DDR3 supporting. But you have DDR2 RAM's. So you would have to go for those boards which support both AM2+ and AM3. Unless you want to change RAM's to DDR3 as well.