Here's what i want to know, however- has the PS3 been officially released in your region or did you import this? If imported this is a bit of what Sony was trying to avoid- people getting systems that may not work fully in that region.
The main thing seems to be your tv is likely an older model and not capable of handling the resolutions being used in games these days. For now you will have to settle for the downscaling to 480p or consider shopping for a new tv.
Word is there will be a big update coming when the system launches in Europe and the UK in March- whether this issue will be one of the fixes is unknown and likely won't be said until it is closer to release.