Well like I said, you need to find emulators specifically programmed to run on the PS3 in order to do this, and we don't usually deal with those kinds of emulators here... If you want a personal PC to run these kinds of things it generally better to just buy a... PC.
A home theater PC can be built or purchased pretty inexpensively these days, and then you'll be able to play DVD's, some PC games (depending on the graphics power required, HTPC's don't usually come with great acceleration capabilities) all the usual roms and emulators for most systems that don't require heavy 3D emulation, etc.. Easily hooked up to a TV with an HDMI port, or at least using DVI or component output (VGA sucks even though TV's include standard VGA. It's very limited)
So those are your two options.. search google or other console-oriented emulator forums, or buy an HTPC