LsPush needs to be run on the client machine. You can manage this via Group Policy or by defining scheduled tasks remotely. Be sure that you put LsPush.exe onto a shared folder which is accessible by all clients and define a schedule to run this executable with the correct parameters in order to send the results to your Lansweeper server.
For instructions on how to use LsPush.exe, please refer to
this KB article.
Here you can find instructions on how to schedule tasks remotely:
http://technet.microsoft.com/en-us/library/cc766266.aspx