Connecting Home Theatre to PC and HDTV and PS3

Hi,

I have a Sony DAV-TZ215 (http/www.sony.co.in/product/dav-tz215) home theatre system which has the following connectivity ports:
1 HDMI Out
1 Analogue Audio In
1 Composite Video Signal Out

I have a 40 Inch Sony HDTV KLV-40EX430 (http/www.sony.co.in/product/klv-40ex430) which has the following ports:
2 HDMI In
2 Composite Video In
1 Component Video In
1 RF Connection In
1 HD15 PC Input/Audio (I don't know what this is, but I think its a VGA port maybe?)
1 Analog Audio In
1 Audio Out
1 Headphone Out

I also have a PS3 with the standard connections.

I also have a set top box which has a composite video and audio out.

At the moment, my PC is connected to the TV through an HDMI port. The Home Theatre is also connected using the second HDMI. The audio out of the set-top box is connected to the Home Theatre and the video out of the set-top box is connected to the TV directly.

So basically, right now I get sound out of the Home Theatre while watching TV through the set-top box or while playing movies on the Home Theatre itself.

What I want is, to connect the home theatre to my TV and PC.

My PC has a 5 channel audio out (3.5mm ports) and it has an optical out port as well.

I'm OK if I don't get sound from the home theatre while watching TV from the set top box.

Is there any way I can use my PS3 to connect everything together?

All these things are in one room so any kind of connectivity will be acceptable.

Kindly help me with this!