Connect to PSN to sync trophies?

Hey guys,

I'm looking for a way to connect temporarily to PSN in order to sync trophies. I'm not interested in gaming online, although I suppose that whatever I have to do, both will work or none.

Is there any way to do it without having to use dongles or similar?
I have the 250gb slim model (I believe it's the first slim model that came out).

Thanks a lot :)

EDIT: If it's an option, I wouldn't mind upgrading/downgrading.