Ok, on a serious note, what do you want to achieve from the post processsing?
I did a simple auto levels and curves adjustment in PS and it brightened it up.
Its slightly 'noisy' (grainy) as I'm working on a compressed file and also due to slight underexposure and your camera used. The pic can still improved with 'noise' removing software or more work in PS. I'm lazy to do it and also quite pointless unless you provide the original resolution file to work with.
Maybe next time when you take a photo like this, you'll have to be careful of the bright patch that will cause an overall underexposed metering. Fill in flash or meter and compensate (if your camera does not have spot metering).