As to which to use C++ vs C# ? The C# is the newer and some would say the
wave of the future but so many programs are already written in C++ and with
the managed environment that .net gives it may the better of the two.
 About C++ vs Visual C++, it really depends on what IDE your company uses.
There are a few small differences in headers etc with Visual C++ but you
might look at what others tell you about which they prefer and why. I like my
Visual C++ because it runs very smoothly especially after downloading and
installing the free processor packs 5 and later 6 that make it run more
readily  on XP and my old computer---slick !!
....So I would suggesting keeping your C and adding Visual C++...but again
just get more opinions...especially where you will be working...and check the
want ads and see what employers are asking for the most in your area.

I use both: C# mostly for "qick & dirty" ad-hoc apps, C++ for anything
that may last longer.

BTW, Eckel teaches old-style C++. Better look at Lippman's "C++ Primer"
or "Accelerated C++" by Koenig& Moo.