Sony KP-57HW40 with PS3 Max resolution?

[kathleenjunk]

Hi: I fully admit to being a total Newbie....I have an older rear projection Sony DP-57HW40 TV and have just bought a PS3 for my son's birthday. (Well, maybe it will get here by his birthday, but Walmart customer service screwed up royally :-)

The owners manual for the Sony KP-57HW40 says: "HiScan 1080: Enables you to receive the 1080i, 720p,480p,and 480i digital TV formats. by using the Video 5/6 IN jacks, you can connect a DTV(digital television) receiver to view DTV programs."

I do NOT have a digital receiver or any satellite digital receiver. But if I connect the PS3 to the TV (using red, green blue wires), what is maximum resolution I can expect (when playing blu-ray DVD movies)? I read about a different connector (HDMI?) but I'm guessing that this TV doesn't accept that connector.

Advice? Any advantage to buying HDMI? with or without HDMI will I get any kind of HiDef picture with PS3/bluray? Anything else I need to buy (other than a DTV, since I"m not ready to spring for that!

Thanks for any advice for an ignorant newbie!
Kathleen from San Francisco Bay Area