Monitor related thing

[Kaze]

Hello,

I basically do not have a TV now. My computer was linked to the TV. I am now left with a 19" Acer PC monitor. The monitor has the VGA option and the power option. What I want to do is link my PC and my PS4 in the future so both systems play through one screen. Below I will show you what I am thinking of doing and would like to hear your opinion on it.

I would purchase this and plug it on the back of my PC monitor. (http://www.amazon.co.uk/Valueline-Cable-Splitter-VGA-Plated/dp/B0014KZ014/ref=sr_1_2?ie=UTF8&qid=1403516368&sr=8-2&keywords=vga+splitter)

One of the leads will connect the PC to the Monitor and the other will link the PS4 to the monitor. The PS4 has only the HDMI cord as it is obv next gen. I thought that maybe I should plug this product to the product i would purchase above. (http://www.amazon.co.uk/Converter-Adapter-Desktops-Power-Free-Raspberry/dp/B009CRN810/ref=sr_1_1?ie=UTF8&qid=1403516585&sr=8-1&keywords=hdmi+to+vga+with+audio)

I would also buy this so that the audio can be split from the PC and the PS4. Both systems will run through speakers (not at the same time)(http://www.amazon.co.uk/StarTech-com-6in-Stereo-Splitter-Cable/dp/B0000DIESU/ref=sr_1_3?s=computers&ie=UTF8&qid=1403516733&sr=1-3&keywords=audio+splitter)

So I have a few questions regarding this idea.

How will I be able to change the source if I want the PC or the PS4? (If they are both on)
Will the picture and audio quality be a significant change with all of the things above?
Can you suggest a similar idea that will work?

The monitor is an Acer V193w

Please do not recommend to purchase another monitor because I am trying to cut down on costs as much as possible. I also have a smartphone and a laptop therefore the second screen is not needed.

I would like to say that I was told numerous of times that once I go small (screen size) I'll never go back as your gaming experience is different than playing with a 32"" or 37"" screen hence why I am willing to try this out.

This is what I'm trying to do but also including my PC -

[SugarD]

If you're trying to split the signals, they do make VGA switch boxes, as well as audio cable ones. They are just difficult to find.

[Kaze]

How can I not think of that 

[TheRock]

Be aware that by splitting the signal, there will be loss of quality (Most of the cases it does happen).