Need to elevate permissions without UAC pop ups

I have an application which is a launcher for another application (my main one). The launcher goes to an FTP server, downloads updates and installs them. However, the update executable needs to copy some DLLs and EXEs to the installation directory of the main application, which is in Program Files. Because of that, I currently need to elevate the rights of the updater.

This is a problem because my application starts on boot, and in general will simply load to the system tray (the application is comparable to messenger/skype). If I start popping UAC warnings on the screen while trying to "silently" update the application, it's not so silent any more.

The only way I see right now to avoid the problem is to give all users permissions to the program files installation directory, but I am reluctant to do that. Any other ideas?

I'm using Windows 7, and the applications are in C#.