We want to accomplish two things here: first, install the latest version of R and second, install RStudio, which is an Integrated Development Environment (IDE) for R.
Let's start by going to R's homepage at https://www.r-project.org/. This page will look similar to the following screenshot:
You can see that there is a link, download R, and in the News section the latest R version is 3.3.2 (Sincere Pumpkin Patch), which was released on 2016-10-31. Version 3.3.3 is scheduled for release in March. Now, click one of the links, either CRAN under Download or download R under Getting Started, and you will come to the following screen, which has CRAN Mirrors:
These are the links, by country and sorted alphabetically, that will take you to the download page. Being in the USA, I will scroll down and find many links available:
Once you find a similar link that is close to your location...