Please post a layout.

From what you wrote you have me confused as to ..

#1 ps3 to monitor
#2 computer to ps3 to monitor

I don't play consoles so.. fill in some blanks for us.
link1 link2 link3 hope to god you have dvi dvi-hdmi adapter stereo/rca/audio/shit

Your issues are gonna start if you think its a plug in play solution to go from Analog to Digital.

DVI to hdmi is the same thing its Digital.
Either get a adapter or a cable adapter.
they are like 9 dollars to like 25.
I get like monster cables etc so yeah.. audiophile/videophile stuff.

buy a new monitor... don't buy an adapter box with multiple connections thats so tacky specially if you would rather buy that then a monitor. Cuz that old shit is gonna be outdated soon anyway. don't buy a analog to digital box thats also retarded for your situation. I would buy only what you need since your wanting to save cash anyway. If you want to use your pc and the monitor for another computer or ps3 KVM switch or that second output on your ps3.

I just thought i would just blabber some things down first then clean it up later once i get a better layout description of A goes to B goes to C goes to ?!

connectors?
Optical av-multi 3x rj45 2x usb 2xhdmi