You could try and get a
component cable for your ps3 if your tv has component in (3 sockets coloured red, green & blue) which also has analog audio to connect to the aux in on your home theatre system. You won't get 5.1 dolby digital this way but you will still get lots of good noises
Alternatively connect your dvd using the scart and ps3 to hdmi (not a good plan . Only suggesting if funds are really limited)
Think someone has said get an hdmi switch.
Or how about a new telly with 2( or more) hdmi in?
