You can usually add packages to R unless there's a dependency on a specific R version. My quick googling doesn't seem to indicate that this is,the case.
Install.packages("car")
What happens if you the code in R, do you get an error?
You can find the relevant version of R here:
http://blogs.sas.com/content/iml/2013/09/16/what-versions-of-r-are-supported-by-sas.html
R is open source, there is an enterprise version the comes with support, EnterpriseR that had some extra features that was taken over by Microsoft. SQL Server 2016 will be shipping with R installed.
You can download R from r-project.org.