So I talked to a friend of mine, Joe, who is a very amazing expert at computers. So I asked for help, as I value his opinion highly.
He said that it's just best to replace what I need to in my current PC, as there's nothing wrong (as far as I know) with my hardware. Everything's fine. The ODD, HDD, MOBO, sound (though the onboard sound doesn't work, so I use an external sound card), video card, etc. Everything's fine. I just want a more powerful CPU, GPU, and a new PSU.
The link I gave with my $600 "gaming" PC works for me. But I want a more powerful CPU and GPU.
He said to get these:
I still need a good CPU, so any tips on that would be appreciated.