Just got a problem with my SL...

All day I was driving it and it was fine, then I went to cafe for 7 minutes and came back to the car. It opened normally, when i putted my key into starter everything turned on: radio, all little lights and etc. But when i tried to start it, suddenly it was like trying to start engine little by little and crashing... I tried like for 35 minutes... Nothing. Left the car for 2 hours and came back again. Again was trying to start it, first it was hardly starting, but engine turned on and got a yellow lamp on display. Showed in attached image. I tested it one more time, lamp don't go away and engine starts badly now, always with time of trying to start...
I hope you understood... Any ideas what happened and how much it will cost me?