de Museumserver

I have owned the attached oil painting since 1980.
A oil portrait of a German Monk - size 20" x 24".
It is by the artist Conrad Herrmann
Born in Berlin, August 23, 1935, and studied at "Berliner Meisterschule
bei Verkerk".
Further studies in other German cities, Austria, Holland and in Ibiza.
One of the well known German portrait painters.
Please advise what the market value of the painting is in $US and if you would know of any buyers?

I too own a Conrad Herrmann and I am not very familiar with this painter, I would really appreciate any additional bio that I could obtain from this fine German Painter as well as a possible auction record. Thank you in advance for your help.
Regards,
Robert Seago