Can I use C#/.NET as a cross platform technology if so how?

Question

I just recently came over to the .NET side of things and I just like it better then everything else I've experimented with but I don't know truly how flexible .NET is. I also have a lot of complementary software to go along with the .NET technologies I'm trying to learn(WPF, WinForms, Silverlight, XAML, ASP.NET, etc.). This is my setup Visual Studio 2012 Ultimate, Expression studio 4, Infragistics & DevExpress User Interface controls along with Telerik Rad Controls (along with all the RED GATE Goodies). all three of these companies state that their products will help me port to all three technologies (Android, Windows 8 & IOS). Is this possible with what I have and if so whats the best way of doing this? The reason is I have to right a program that will function on a device with an embedded system like IOS, Android or Windows 8 Device and I don't wanna have to put aside learning .NET for this one project. I would appreciate any advice or knowledge you have to offer.

Please Help

Thank You!!!