Limit what you do with the phone for the moment. Everything that writes to the sdcard means less you might be able to retrieve. Not for sure about this because its Android but it makes sense it wouldn't be that different from Windows and all it did was rewrite the registry.
PC app tuneup utilities has a very good undelete pluggin that you can restore to a different disk than original.
I'll look around and see if I can find a good free app that will do it.
Hope this helps.
When you plug your phone in via usb and mount usb mass storage your pc sees your sdcard like any other disk drive. If your phone doesn't connect properly you will even get the please insert disk message.
If it has to stick the files back in the original location remove your sdcard from your phone and use a sd usb adapter and let it put them back on the card and transfer them to the pc directly then right click the drive and choose reformat let it do it then eject it and stick it back in your phone and reboot. It may prompt you to format it again if so let it.