Can someone help me with finding a good gaming desktop please

Ok, I am new to this site, but it looks like a great place to start.
I am currently using a laptop computer, but am having problems with it and would like to get a desktop for a seriously better gaming experience. I will be using the computer to play World of Warcraft, use facebook and surfing the web, such as ebay and that sort of thing. My budget is about $500, if I have to go a little over I may be able to come up with $600. I have never built a computer and have no idea how to get started, but I hear it is cheaper. So, I would kind of like a pre-built or is there any websites that build it when I order it or anything? If it really isn't hard to do or someone has a really good guide on how to build one that would be great, and I may be able to try it, I'm just worried about ordering the stuff and then not being able to put it all together... I will be building completely from scratch as I have nothing yet, so I will also need all of the peripherals.
Thanks ahead of time, I really appreciate any and all help! =D

Also I do not know a lot of computer jargon, I am learning as I go
 
Back