My recommendation is to learn C#.
C#, and the .NET libraries it is built on, are really the only development system for Microsoft Windows Desktop ( PCs ) and Web Servers, in my view.
Reading
The following book could be slightly basic, but is probably a good book for beginners, maybe you could skim it if you find it easy:
Programming in the Key of C#: A Primer for Aspiring Programmers
by Charles Petzold
'Compose your first software applications with programming maestro Charles Petzold.'
http://www.microsoft.com/learning/en/us/book.aspx?ID=6261&locale=en-us
Charles Petzold has been on the Windows development book scene since the year dot, and I am sure this is a good book.
Demand for Skills in the Job Market
Here are the top 10 software skills in job advertisements, according to JobsAdsWatch:
http://www.jobadswatch.co.uk/jobstats/trends/topskills
http://www.jobadswatch.co.uk/jobstats
(Notes: 1.I think C is still in demand because of the number of existing applications that use it, but not for new development; 2. SQL and SQL Server would be in demand because these skills would almost always be asked for as secondary skills in a development job, in any main programming language. On their own they would not be a primary skill for developers.)
At the end of the day, you have to make your own decision, and what I have said may not be at all suitable for you. You will need to evaluate all this for yourself to decide what is suitable for you, based on facts your are comfortable with yourself.