you should use the github, there are a couple small updates and bug fixes there.
https://github.com/fyaconiello/wp-geo-posts
in the bottom of the readme there is an example w/ a radius.
A couple known unsolved issues:
If you use shared hosting this probably won’t work well. Geoencoding addresses uses Google’s geoencoding service which limits how many geocodes can be done per day PER IP. So if other people are geoencoding on your shared environment there may not be enough encodes for you.
If you have a huge number of geoposts, you will run into another issue. calculating distance on EVERY post before limiting on radius is going to take forever. You can modify my plugin using this: https://www.plumislandmedia.net/mysql/haversine-mysql-nearest-loc/ look at the optimization header to pre-filter before records you are calculating distance on.
