I think updates are not online anymore, so to get them you will need to Jailbreak.
I have recently done so (JB and Mod) and it has opened up a whole new world. I can not recommend it highly enough.
I am now racing GT5 online with "clean" racers in a lovely little community.
If you are interested, please PM me and I will talk you through everything. I have recently done it so know pretty much all about it.
Do it now - I dragged my heels on it and now wish I had done it months ago.