On the other hand, even If it was possible to grab the path and then save it, please have in mind that this is the path to the file on the client machine. The server is a different machine and this path is not applicable to it. I mean that you can't load the files from the server using the path that was available on the client.
Apart from this, you can use RadAsyncUpload to filter the file choice by setting AllowedFileExtensions property.
All the best,
the Telerik team