PHP wordpress Expert.

I have a wordpress site with a directory page that displays a list of all my users that have signed up on my website... the page is written in PHP. I wish to add various filters to the top of the members directory that filters my users by various categories that will be set on their profiles as meta_keys. The website uses buddypress which already has a few basic filters added to the directory. I would like to be able to filter members by their zip_code, with a drop down menu with 5km, 10km, 15km, 20km and so on. For example, a user enters a zip_code, and selects 5km, i want the directory to show ONLY users that are within 5km of that zip code when they click a "search" button. (very similar to gumtree and ebay). I understand to do this i would have to have some form of database that stores zip codes with coordinates, or use a plugin, if you have any advice on how to accomplish this filter that would be great. The second filter i would like is a checkbox for "online now" that shows ONLY users who are online, the current page written in php can already determine whether a user is online or not, i just want to add a checkbox for it. Example: A user checks the "online" checkbox, then clicks search, and it will show all online users. Finally... the current page does not have an option to have multiple pages, it only has an option to display a certain number of users per page, for example "50 users per page". I would like to have the page display for example 50 users, then have an option to go to another page to display 50 more.