Can someone help me choose a motherboard? (WALL OF TEXT!!)

Ok, so my old system’s motherboard (from dell) seems to have up and died on me. I can’t order a new one from them and the computer’s out of warranty by a few months. I’ve decided to go ahead and just purchase a new case, power supply, and motherboard. The only problem is that I can’t identify the processor in the old system because I can’t turn it on :(. Here’s what the dell website says it is.

Processor, Athlon 64×2 For Desktops, 5600+, 2.9, 1MB, 2C 65W, G2

If anyone would be so kind to help me out, I need to know the name of the CPU and/or motherboard socket types that would be compatible with it. I read somewhere else online (in another help forum I believe) that AM2 processors are compatible with newer AM2+ motherboards, which if true would be awesome for me because I can’t seem to find a good AM2 socket board. I’m in need of help desperately because we have some important info on our old hard drive and want to get everything up and running. For reference, the old system is a Dell Inspiron 519 I believe, although I can’t seem to find any of our documentation on it. Don’t be afraid to get technical with me, I’ve just been out of the loop for a year or so. Thanks in advance!