C'mon...You don't know how to flash a rom with Odin ? Not like it's a great secret, you don't need to be a 'power user', this info is easily found by searching (or even looking in the thread stickied near the top of Q&A titled 'Flash stock firmware').
Get a stock rom from Samfirmware, flash it with instructions in that thread. Problems with Odin flash ? Hopper8's 'Odin troubleshooting' thread stickied in General has all the info you need to get a successful flash.
Edit - Also, it was Rom Manager that broke your recovery. Don't use it. Yes, you may have been using it for a long time without problems, but that changed today, didn't it ? Eventually what happened to you will happen to everyone who uses Rom Manager on the I9100. It's unnecessary.
If it's important enough to cause you grief if it's lost, back it up. No excuses
Trolling for thanks is lame
Does Samsung's auto-brightness implementation crap drive you to self-harm ? A solution !
Failure to search is the leading cause of male impotence on XDA
If you don't know how to recover if things go wrong, what are you doing flashing custom roms ?