based on this article:
http://www.gamestar.de/spiele/the-witcher-2-assassins-of-kings/news/the_witcher_2_assassins_of_kings,44750,2324541.html

besides the presentation of the xbox360 version, new content will be shown at the gamescom in late August by CDP RED for the PC. No further details of what it might be, unfortunately. The author is reckoning with more DLC.

Yum, yum! I hope it's something more expansive, preferably something that properly extends the story. :)

I hope / got that feeling, that the X360-version will be the 'Enhanced Edition', so maybe they indeed are showing more than some more DLC.
Maybe CDPR plan on filling in the gaps and obvious loose threads. TW2 seems to be shortened in quite a few places - I guess, they just couldn't complete the content in time for the release and cut what could be cut (quite) seemlessly. The most obvious example probably is Act 3 which feels rather cramped and devoid of content.
That would be awesome!

When they announced the xbox version they said that it will come with some extra stuff.

They also said that the PC version will be getting the same contect as XboX version.

So maybe this is just one extra thing (DLC maybe) - it will be included in the XboX version, but it will actually be something new for the PC, released the same day as the XboX version.

If they released new content for console version but not for PC (like Dead Space 2), I would get on a plane, go to Poland and burn down their office!!!! I'm POSITIVE that won't be necessary, but the Dead Space 2 DLC kick in the teeth for pc gamers make me very angry.

what was the diff with the W1 and enhancedW1 apart from the 2 seperate adventures

It is TW1 with all the patches applied.

Consider yourself very lucky if you didn't have the (dis)pleasure of playing vanilla, v1.0 The Witcher 1.

Quite a few bug fixes and an almost complete revamp of the dialog for non polish versions.

As far as content goes, they only added the new adventures, but The Witcher 1 was already a much more lengthy game compared to the second installment.

I think we need to wait for "official" anouncement from CDP. I'm sure I can rememeber earlier when the Eggbox enhance version was anounced on the witcher web site several people going off at the deep end about if w2 eggbox has new/enhanced stuff in it they were going to "bomb" poland. CDP replied that enhanced ment everything that w2 pc had like DLC and patches. So when eggbox version comes it may well have nothing new.

the news I've posted earlier was updated. According the official word from CDPRed it's a large DLC and is going to be introduced in the form of a video at the gamescom. Apparently the DLC is a part of a not yet announced update.

Edit: missed the other thread: http://www.gog.com/en/forum/the_witcher_2/big_dlcs_are_coming