FYI - Here is some info on how Library Server works - http://wiki.jriver.com/index.php/Library_Server
It is pretty straight forward (if you know what you are doing), especially if all you PC's are part of the same "HomeGroup" - have a read of the MS article on this -
http://windows.microsoft.com/en-au/windows7/share-files-with-someoneIf you want to go down this path you would need to:
1) Create the Share on the PC with the Media (eg you right click on the top level folder underwhich all the media is stored in Explorer --> Share With --> Home Group (read or read/write pending you preference). All PC's on your homegroup should now be able to browse the contents of this folder in Windows Explorer --> Network --> PC Name. Make sure this works before moving on
2) Change the filepath in you Library Server Library to the UNC path name (eg from say G:\Media\movie.mkv --> \\"SHARENAME"\Media\movie.mkv). MC will do this for you if you select all your media --> right click --> library tools --> Rename, Move, & Copy Files then use just the "Find & Replace" option with the Drop Down option "Update Database to point to new location) selected. Check that both your Server and Client PC's can play the media. In the future you would import all media from this share not the physical location so the path is always in the correct format.
It is a quick and easy change BUT - if you are not used to these things it may be better to get someone who does to come around. It may also expose a different issue that your WiFi network is not strong enough to play original material over it... so converting may still be your best option.