Upgrading my PC for Dolphin?

My PC is slow and it can run GC/Wii games fast.I was thinking to upgrade it so it can at least play some of
the games with proper speed.

My PC's specs are:

MB:Gigabyte M61SME-S2L
CPU:AMD Athlon 64 X2 5200+(2.8 GHz)
RAM: Single slot 1GB DDR2 800 MHz
Video:Onboard nVidia GeForce 6100 nForce 405
Running:Windows Vista Ultimate SP2 32 Bit

Soooo slooooow

Configuration I:

MB:Gigabyte M61SME-S2L(I will keep it.It supports AM2/AM2+ Processors)
CPU:AMD Athlon II X4 640 (3 GHz)
Ram: Dual Slot 6GB DDR2 800 MHz (The motherboard supports up to 8GB DDR2 so it should be ok)
Video:Sapphire R7 250 1GB GDDR5
Running:Windows 7 Ultimate 64 bit

Configuration II:

MB:Gigabyte M61SME-S2L
CPU:AMD Phenom II X4 980 (3.3 GHz)
Ram: Dual Slot 4GB DDR2 800 MHz
Video:MSI GT 630 4 GB GDDR3
Running:Windows 7 Ultimate 64 bit

Configuration III:

MB:Gigabyte M61SME-S2L
CPU:AMD Phenom II X3 740 (3 GHz)
RAM: Dual slot 6GB DDR2 800 MHz
Video: MSI GT 640 2GB
Running:Windows 7 Ultimate 64 bit

My only problem is that I can't find neither the Phenom II X4 980 nor the Phenom II X3 740,but I will try to find at least one of them.

Sorry for the bad English,it's not my native language.