How to get the path of the selected Image in Adobe Bridge via Applescript?
I think you would have to go via Photoshop using BridgeTalk to get the path.

function getPathFromBridge(){
    function script(){
        var Path = new File(encodeURI(app.document.selections[0].spec.parent)); 
        return Path.toSource();
    }
    var filePath='';
    var bt = new BridgeTalk();
    bt.target = "bridge";
    bt.body ="var ftn = " + script.toSource() + "; ftn();";
    bt.onResult = function( inBT ) { filePath = decodeURI(eval( inBT.body));}
    bt.onError = function( inBT ) { filePath = '';}
    bt.send(4);
    if ( undefined == filePath ) filePath = '';
    return decodeURI(filePath); 
}