1992 Mercedes Benz 190e Head Gasket

Engine Mechanical problem
1992 Mercedes Benz 190e 4 cyl Wheel Drive Type unknown Automatic 130000 miles

I just purchased this used 1992 Mercedes 190e 2.3 about 1 month ago & was told everything was fine with the car. I brought it in for a tune up & $1600. Worth of work on it, was now told I need a new head gasket & radiator. They quoted me at about $1700. I didn't have the money & told them not to do the work & I took the car home. Does that seem like a fair price for that work to be done? Also, I've been driving the car around since I got it back 2 weeks ago, but will this do more damage to the engine & about how long before it starts stalling out on me? I paid $2000. For the car & not sure if it's worth putting more money into it. Any help with this will be appreciated.