About Pokemon new versions

Hey guys, im planning buying a 3DS XL along with Pokemon, i stoped played pokemon till Diamond/Pearl some years ago, what i want to know is whats the difference between white/black and white 2/black2 (main difference) and second... can i pass all my pokemons from diamond in to these new version?

Black 2/White 2 are the sequels to Black and White. It has a different story (sets 2 years after BW), new and returning characters, new locations, etc. I recommend playing Black or White before Black 2 or White 2.

Yes, you can transfer pokemon from Diamond to BW/B2W2, but only after you defeat the Elite Four, unfortunately. Older pokemon (pokemon from Kanto - Sinnoh) are not available in Black and White before defeating the Elite Four, but there's a good amount of old and new pokemon diversity in B2W2 before and after the Elite Four.

I see, thanks for the responses; ill be hitting this game then, would love to use all my pokemon from kanto/jhoto and the ones i collected since Ruby. Have a good one!