Unable to boot mac mini after interrupted upgrade from 10.7.2 to 10.7.3

I purchased new Mac Mini (Mid 2011 Model) 5 days ago. Last night, I started to uogarde it from Lion 10.7.2 to 10.7.3 using the DMG file provied by apple for update.

The upgrade was interuppted automatically by a system crash and I was shown a message in 5 languages to hard boot long pressing the power button.

When I hard booted the system is constantly showing gray screen with the Apple Logo and a spinning progress bar.

I read the manual and tried to boot in safe mode but it did not start in safe mode.

I also - Reset the NVRAM / PRAM, nut even this did not help to boot successfully.

I also read the KB article (Mac OS X: Gray screen appears during startup) and tried the steps mentioned there but I can't perform many of the steps mentioned there as the Mac mini does not has Optial drive so that I can install Lion afresh.

I think I need to install Lion afresh, So my question is what will happen to my license of Lion OS that was factory installed in my Mac mini?

Please help and guide me.