Not able to find System.Web.Optimization in asp.net

Hi,
I am trying to update my visual studio with the latest released Nugget in the Package Manager console but I am getting this error:
Install-Package EntityFramework -Version 6.0.0-alpha2 -Pre
Install-Package : Cannot bind parameter 'Version'. Cannot convert value "6.0.0-alpha2" to type "System.Version". Error: "Input string was 
not in a correct format."
At line:1 char:42
+ Install-Package EntityFramework -Version 6.0.0-alpha2 -Pre
+                                          ~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [Install-Package], ParameterBindingException
    + FullyQualifiedErrorId : CannotConvertArgumentNoMessage,NuGet.PowerShell.Commands.InstallPackageCommand

I am using MS VS 2010 and  Microsoft.NET Framework Version 4.5.50709 SP1 Rel and I have win 8 installed on my PC
and the reason I am trying to install is becuase I want to reference a namespace in the Global.asax file which does not found the BundleConfig in the namespace
and when I am trying to reference it from System.Web.Optimization it giving an error.

this is the code I a using in the Global.asax:

namespace WingtipToys
{
    public class Global : System.Web.HttpApplication
    {

        void Application_Start(object sender, EventArgs e)
        {
            // Code that runs on application startup
            BundleConfig.RegisterBundles(BundleTable.Bundles); at this line of code

        }
Please can someone help fixing this.