C++ and C#

I have read some articles that in the future the C++ language will extinct.
That is because C++ does not support .NET.
Since I am a user of Borland C++ Builder, I am used to it, i got concerned about this.
Anyway I have looked at some freelance sites and no one hires C++ coders. Everybody needs coders which are familiar with .NET. This may be why the C++ language is extincting.
I do not really know what is .NET, but as far as I can see it's a must for a coder, since all the work places provided require you to know .NET.

So this means, if in future I will want to work as a coder I will need to switch coding languages.

I have heard that the most similar language to C++ is C#.
But since I don't really know the native C++ and also because I am so in love with the Borland objects (like TStringList's, TSocketClient and all the others) this may be a problem to me.
I would really like to know, which csharp IDE is the most similar to the Borland Builder. Maybe some of the IDE's have it's own objects like Borland C++ Builder does? Also one thing that I have been missing while looking through the MS Visual Studio screen shots is the GUI creator. I would also like and IDE which would have a GUI creator. Since I will be mostly coding on Windows. Also BCB had a neat help file which had examples and everything in it.

Anyway I have made the decision that If I will want to work as a coder later on I have to switch languages now. Please help me find the best surrounding which would be the most similar to the Borland one. I also require it to have the neat help where everything is explained, from A to Z with examples and neat tricks.

Or maybe you know a way to integrate .NET into Borland C++?
Or maybe you think that my decision is wrong?
Also please describe .NET.  What is it? Whats the purpose of it? As easy to understand as possible. That I could explain it to my thirteen year old sister.