I want to keep my motherboard but upgrade my...

[Grim Presence]

my motherboard's model number is 'M2n61-ax' my computer is currently running on AMD Athlon 64 X2 4000+. i want to upgrade my processor to one of these four listed:
AMD Athlon 64 X2 4800+( AMD Athlon 64 X2 5200+ AMD Athlon 64 X2 6000+ AMD Athlon 64 X2 6400+

 

[Grim Presence]

my motherboard's model number is 'M2n61-ax' my computer is currently running on AMD Athlon 64 X2 4000+. i want to upgrade my processor to one of these four listed:
AMD Athlon 64 X2 4800+( AMD Athlon 64 X2 5200+ AMD Athlon 64 X2 6000+ AMD Athlon 64 X2 6400+

i don't know what to do or where to search to know what is right for me to safely make a choice on the part to put in my computer.