Is this gen’s console about to end and be replaced by the xbox 720, ps4 etc. Are those even official yet and is there a release date?

I have both Playstation 2 and 3! And I’m wondering if they’re going to make a Playstation 4! Are they
going to make a PS4?

i want to buy a ps3 but no stores have it. target,walmart,and kmart don’t have it.what i want to know is if sony is going to improve something or maybe even bring out a ps4. i want to know before i buy it at gamestop, because i dont want 2 buy it and then have a improved ps3 come out or possibly a ps4. please answer with details