Converting interpreter query to local query.

I'm planning on writing a small phone application which will show the users the current street and speed limit, I found that this information is easily accessible on the following link:

http://overpass-api.de/api/interpreter?data=[out:json];way(around:10,53.6788398,-1.4992124)[maxspeed];out;

But since this will be a real time app and each user will probably ping the server at every 5 seconds, I have concluded that it will be against the current server fair usage limit so I have deployed a local copy to my own server, however I do not want to use the interpreter with Apache I will like to use my own php script which calls osm3s_query but I couldn't find a way to translate above query to work from the command line.

I have read the documentation found here: http://wiki.openstreetmap.org/wiki/Overpass_API/Language_Guide#.22around.22_-_finding_something_near_something_else about the around, but it doesn't give any explanation about how to use it with lat/long and creating a bounding box for this feels like an overkill to me.

As question number 2, is there any way to reduce the deployed osm data? I only need street names and speed limits, I do not need everything else, but I need this for the whole globe, and I need to updated it on daily or weekly basis. Again having a full OSM synced to my server fills a huge overkill.

Thank you.